APPENDIXES



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APPENDIxES

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Appendix A Gun Enforcement and   Ballistic Imaging Technology in Boston Anthony A. Braga∗ In March 1995 Boston was one of the first major cities to receive Inte- grated  Ballistics  Identification  System  (IBIS)  ballistic  imaging  technology  from the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). The  system was considered fully implemented when the Boston Police Depart- ment  (BPD)  ballistics  unit  made  its  first  IBIS  match  in  July  1995  (Braga  and Pierce, 2004). Prior to the adoption of IBIS, BPD ballistics operations  usually consisted of manually matched bullets and cartridge casings recov- ered at a crime scene to determine whether the bullets or casings were fired  from a suspect’s firearm. Firearms examiners in the ballistics unit did not  systematically  compare  bullets  and  casings  from  one  scene  to  ballistics  evidence  recovered  at  other  crime  scenes  to  determine  whether  separate  gun  crimes  were  linked.  When  BPD  firearms  examiners  did  attempt  to  make such matches, known as making “cold hits,” it happened in one of  *Program in Criminal Justice Policy and Management, John F. Kennedy School of Govern- ment, Harvard University. This research was supported by funds from a number of sources,  i  ncluding  the  National  Research  Council,  the  National  Institute  of  Justice,  Forensic  Tech- nology WAI, Inc., and the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). The  author  would  like  to  thank  the  members  of  the  committee  for  their  helpful  comments  and  suggestions  on  this  work.  Thanks  are  also  due  to  Special  Agent  Terrence  Austin  (retired),  former director of the ATF National Tracing Center; Marianne Hinkle, former Assistant U.S.  Attorney, District of Massachusetts; Assistant District Attorney Raffi Yessarian of the Suffolk  County (MA) District Attorney’s Office; and Commissioner Kathleen O’Toole, Superintendent  Paul  Joyce,  Deputy  Superintendent  Paul  Fitzgerald,  Deputy  Superintendent  William  Casey,  Sergeant James O’Shea, Sergeant Kathy Doherty, Sergeant Mark Vickers, Sergeant John Daley,  Detective Earl Perkins, and Carl Walter of the Boston Police Department. 9

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9 BALLISTIC IMAGING two  ways:  (1)  the  firearms  examiner  may  have  recognized  some  unique  markings on a cartridge casing as very similar to markings on a cartridge  casing recovered at another crime scene; (2) a detective would develop an  investigative lead from a confidential informant that a recovered crime gun  had  been  used  previously  in  another  gun  crime  and  request  the  firearms  examiner to make comparisons of evidence across the crime scenes (Braga  and Pierce, 2004). Since  adopting  the  IBIS  technology,  it  has  become  BPD  policy  to  test  fire all recovered crime guns, and the expended bullets and cartridge casings  are  imaged  and  entered  into  the  IBIS  database  (Braga  and  Pierce,  2004).  Importantly, the BPD makes an aggressive effort to collect, image, and enter  ballistics evidence from all incidents involving firearms—ranging from homi- cides  to  illegal  possession  cases  to  suicides—into  the  IBIS  database.  Only  noncrime guns that are held by the BPD for safekeeping are not imaged. The  BPD refers to this process as comprehensive imaging of all crime-related bal- listics evidence. In sharp contrast, in the pre-IBIS period, cartridges or bullets  from  different  crimes  scenes  were  cross-examined  by  firearms  examiners  only in extreme circumstances or when there was a suspicion two criminal  events  were  connected.  As  of  December  31,  2003,  the  BPD  ballistics  unit  had entered some 2,400 bullets and 12,700 cartridge casings into its imaging  database and had recorded 412 confirmed IBIS-related matches.1  THE uSE OF IbIS MATCHES IN guN vIOLENCE PREvENTION STRATEgIES Confirmed  IBIS  matches  are  a  key  part  of  the  BPD’s  gun  violence  reduction strategy, the Street Violence Suppression Project (SVSP).2 Every  2  weeks,  the  Boston  Police  convene  an  interagency  working  group  com- prised of BPD officers and detectives, ATF agents, assistant U.S. attorneys,  assistant  Suffolk  County  district  attorneys,  Massachusetts  State  Police,  Massachusetts  probation  officers,  Department  of  Youth  Services  (juve- nile  corrections)  case  workers,  and  other  criminal  justice  practitioners  as  1  he original study reported 396 matches made through the first week of December 2003  T (Braga and Pierce, 2004). The BPD ballistics unit has been imaging ballistics evidence for other  local police departments that share gun crime problems with Boston (Braga and Pierce, 2004).  For example, there are strong street gang connections between Boston and the communities  of Brockton (MA), New Bedford (MA), and Providence (RI) and gang-involved gun criminals  tend to travel between the cities. 2  he SVSP was the latest incarnation of the Boston Police Department’s evolving strategic  T response to gun violence among serious offenders. Earlier versions of BPD strategic violence  prevention initiatives include Operation Ceasefire (Kennedy et al., 1996; Braga et al., 2001),  which was in place between 1996 and 2000, and the Unsolved Shootings and Impact Player  Assessment Project, which was in place between 2001 and 2004 (Braga and Pierce, 2004). As  of January 2007, the same process is now part of the BPD Compstat process.

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9 APPENDIX A needed. This meeting serves as a scanning and analysis forum for ongoing  conflicts among violent gangs and other gun incidents with high potential  for retaliation. After specific violence problems are identified, BPD officers  and  detectives  are  assigned  responsibility  for  devising  and  implementing  appropriate violence prevention plans to halt outbreaks of violence. Strate- gies are developed at a separate response development meeting; however,  implemented  plans  and  progress  updates  are  presented  at  the  bi-weekly  meetings to disseminate knowledge on what works (and what doesn’t) and  to  hold  officers  responsible  for  keeping  targeted  groups  and  individuals  from shooting at each other. At the SVSP scanning and analysis meetings, BPD crime analysts and  intelligence officers present information on gun incidents over the previous  2 weeks. Recent IBIS matches are highlighted at the beginning of each meet- ing.  Members  of  the  working  group  discuss  the  circumstances  associated  with the linked incidents; information developed through interviews with  arrested offenders, victims, and witnesses; available intelligence on current  “beefs” between gangs or the activities of serious violent offenders in the  linked areas and analyses of other physical evidence collected at the crime  scenes, such as DNA and fingerprints. If guns are recovered and successfully  traced by ATF, information on the first retail purchaser and licensed dealer  are  presented.  In  essence,  an  “information  chain”  is  constructed  around  the events linked by ballistics evidence. The amount and types of informa- tion associated with linked gun crime events can vary tremendously across  matches; see Figure A-1.  All matches provide investigators with the caliber, crime types, dates,  times, and locations of shots fired from a particular gun or from a recovered  gun  that  is  subsequently  test  fired  by  BPD  firearms  examiners.  However,  other  key  information  that  may  be  critical  to  solving  a  particular  violent  crime may or may not be available to investigators, depending on the nature  of the incidents linked by ballistics evidence. To understand what happened  at  a  crime  scene,  investigators  have  to  rely  on  information  provided  by  witnesses,  victims,  and  arrested  offenders.  Whether  these  individuals  are  present varies across crime scenes. When they are present, the information  provided  may  or  may  not  be  very  helpful  to  an  investigator  for  a  wide  variety of reasons. Witnesses and victims may not know the identity of the  assailant(s). Witnesses may not want to share information with law enforce- ment  agents  because  they  fear  reprisals.  Victims  may  be  active  criminals  who prefer street justice for their assailant(s) to the slow justice of the legal  system.  To  avoid  self-incrimination,  arrested  offenders  may  not  provide  investigators with any useful information. The presence of other physical  evidence, such as DNA and fingerprints, and law enforcement intelligence  on violent criminals feuding in the affected areas will also vary across crime  scenes. 

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9 BALLISTIC IMAGING Ballistics Evidence Link • Caliber of firearm Gun Crime Gun Crime Event 1 Event 2 Information that is Information that is If a gun is always available always available recovered • • • Type, make, Crime type Crime type • • model Date of crime Date of crime • First purchaser • • Time of crime Time of crime and dealer for • • Location of crime Location of crime traceable gun • Other physical Information that is Information that is evidence sometimes available sometimes available (fingerprints, and variable in quality and variable in quality DNA, etc.) • Witness interviews • Witness interviews • Victim interviews • Victim interviews • Arrested offender • Arrested offender interviews interviews • Intelligence on violent • Intelligence on violent groups, individuals, groups, individuals, and conflicts in area and conflicts in area • Other physical • Other physical evidence (fingerprints, evidence (fingerprints, DNA, etc.) DNA, etc.) FIguRE A-1  Types of investigative information linked by IBIS-suggested matches. A-1.eps While ballistic imaging makes an important investigative link between  two gun crime events, the availability of key information that may be criti- cal to resolving crimes depends on random situational characteristics of the  linked  events.  An  IBIS-suggested  match  that  links  cartridge  casings  from  shots  fired  from  two  locations  with  no  witnesses,  victims,  or  suspects  to  interview and no other physical evidence left at the scenes has low immedi- ate potential for making arrests. An IBIS-suggested match that links a gun  assault with victims and witnesses willing to talk, to a gun possession case,  in which a gun is recovered and an offender is arrested, is much more likely  to generate an arrest for the first gun crime. However, while more evidence  is  available  to  investigators,  arrests  and  successful  prosecutions  are  not  guaranteed.  Leads  from  ballistic  imaging  link  guns—not  individuals—to 

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9 APPENDIX A crime scenes. In linked guns, a different person could have committed the  first crime. For example, the first actual shooter may have subsequently sold  the gun to an unidentifiable street drug dealer who then sold it to the illegal  possessor apprehended in the second crime.  The  resulting  information  chains  that  are  constructed  around  gun  events  have  value  to  law  enforcement  officials  in  two  ways:  (1)  holding  offenders accountable for their crimes and (2) guiding violence prevention  efforts on risky groups and individuals. Obviously, law enforcement agents  want to arrest violent gun offenders; making links across events can gener- ate  important  leads  that  may  result  in  the  apprehension  and  prosecution  of gun criminals. However, IBIS-suggested matches also provide important  opportunities  for  Boston  law  enforcement  agencies  to  better  understand  and  respond  to  street  violence.  The  links  help  guide  violence  prevention  efforts by establishing patterns of violence in particular areas and among  specific individuals.  Even  matches  that  have  little  immediate  potential  for  generating  an  arrest can have strategic value in understanding and responding to violent  crime problems. For example, a match between two “shots fired” incidents  with no victims, arrested offenders, and witnesses can be coupled with intel- ligence on active conflicts among groups in the places linked by shell casings  fired by the same gun. The link serves as an early warning sign that repeat  shots are being fired in a particular gang turf area. Based on this pattern,  the  interagency  working  group  focuses  resources  on  gathering  additional  intelligence on conflicts in the area and immediately increases their presence  in the area to prevent additional violence. ASSESSINg THE vALuE ADDED TO bOSTON guN LAW ENFORCEMENT OPERATIONS by bALLISTIC IMAgINg TECHNOLOgy Assessment of Changes in the Productivity of the bPD ballistics unit To measure the effect of ballistic imaging technology on the productivity  of  the  BPD  ballistics  unit,  it  is  important  to  consider  the  nature  of  the  technological innovation and its potential impact on BPD operations. IBIS  is  able  to  cross-examine  large  volumes  of  evidence  and  suggests  a  small  number of candidate cases that may match the evidence in question. The  firearms examiner then carefully looks at the candidate cases using standard  procedures to determine whether a match actually exists. The nature of a  confirmed match and its utility to a criminal investigation does not change  as a result of the IBIS technology (Braga and Pierce, 2004). As mentioned  above, forensic evidence, such as ballistics matches, is one part of an infor- mation chain (such as eyewitness testimony, circumstantial evidence, etc.) 

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9 BALLISTIC IMAGING that leads to the ultimate arrest and prosecution of gun criminals. Arrest  and prosecution is influenced by many factors beyond the forensic link of a  particular gun to ballistics evidence collected at separate crime scenes. Since  the value of a ballistics match to the resolution of a crime is not meaning- fully  different  before  and  after  the  adoption  of  the  IBIS  technology,  the  outcome of interest is the number of matches made by the ballistics unit,  not the ultimate disposition of the resulting cases. As such, Braga and Pierce  (2004) examined whether IBIS changed the ability of the BPD ballistics unit  to link gun crimes. To  determine  whether  the  adoption  of  the  ballistic  imaging  technol- ogy was associated with a change in productivity, the annual and monthly  number  of  cold  hits  made  by  the  BPD  ballistics  unit  was  computed  for  the 14-year time period between 1990 and 2003.3 Figure A-2 presents the  yearly number of cold hit ballistics matches made by the BPD ballistics unit  during the study period. During the pre-IBIS period of 1990–1994, the bal- listics unit made an average of 8.8 cold hits per year. After the adoption of  IBIS, the productivity of the BPD ballistics unit rose dramatically to 60 cold  hits  in  1995  as  the  unit  immediately  entered  a  large  backlog  of  ballistics  evidence into the system. The yearly number of hits decreased during the  1996–1998 period; then, as the inventory of casings in the system grew, it  increased again between 1999 and 2003. The ballistics unit moved to new  BPD headquarters in 1998; the move limited the use of the IBIS equipment  for about 2 months and was associated with the low number of matches  (25) in 1998. Nonetheless, the BPD ballistics unit averaged 45.7 cold hits  per year between 1995 and 2003. The  Braga  and  Pierce  (2004)  analysis  of  the  impact  on  the  monthly  number  of  cold  hits  made  by  the  BPD  ballistics  unit  associated  with  the  adoption  of  the  IBIS  technology  followed  a  basic  one-group  interrupted  time-series  design.  Of  course,  it  would  have  been  ideal  to  have  a  control  group that did not receive the IBIS technology to make comparisons. How- ever,  given  the  ATF’s  National  Integrated  Ballistic  Information  Network  (NIBIN)  program,  there  is  no  major  city  comparable  to  Boston  that  has  a  ballistics  unit  without  ballistic  imaging  technology.  In  addition,  among  major cities, Boston showed some of the most dramatic declines in firearms  crime (Braga et al., 2001); see Figure A-3.4 Consequently, it was also dif- ficult to find an appropriate control city or group. In absence of a separate  control  group,  the  key  to  a  compelling  one-group  interrupted  time-series  3  he findings reported here simply add an additional year of data to the original Braga and  T Pierce (2004) study that examined ballistics matches between 1990 and 2002. 4  The adoption of IBIS was not associated with the drop in gun violence in Boston. Rather,  a focused deterrence strategy designed to keep gangs from continuing their cycles of ongoing  violence was found to be associated with the significant decrease in Boston youth gun violence  (Braga et al., 2001).

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99 APPENDIX A 80 70 60 Number of Matches 50 40 30 20 10 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year FIguRE A-2  Boston Police Department ballistics matches, 1990–2003. A-2.eps 3,000 2,500 Number of Serious Gun Crimes 2,000 1,500 1,000 500 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year FIguRE A-3 Serious gun crime incidents in Boston, 1990–2003. NOTE:  Serious  gun  crime  incidents  are  defined  as  gun-related  homicides,  aggra- A-3.eps vated assaults, and robberies.

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00 BALLISTIC IMAGING design  is  the  degree  to  which  other  forces  not  related  to  the  intervention  influence the outcome variable. If at the time the IBIS technology was intro- duced in Boston the staff of the ballistics unit also changed, this could pose  a problem of a change in “instrumentation” (Campbell and Stanley, 1966;  Cook and Campbell, 1979). However, this was not the case in Boston. As  Table A-1 shows, the ballistics unit staffing level of BPD firearms examiners  remained the same before and after the IBIS technology was adopted; see  the period from 1993 to 1997. For the entire 10-year period, the unit had,  on average, 6 firearms examiners and 10 total personnel on staff. There was  a slight decrease in the number of firearms examiners and a corresponding  increase in support staff, but the only substantive change in the dynamics  of  the  ballistics  unit  was  the  addition  of  the  IBIS  technology  (Braga  and  Pierce, 2004). For an empirical analysis of trends in BPD ballistics matches, July 1995,  the month of the first IBIS cold hit match, was selected as the date the IBIS  technology was fully implemented (Braga and Pierce, 2004). The pre-IBIS  time  series  was  comprised  of  the  monthly  counts  between  January  1990  and June 1995; the post-IBIS time series was comprised of monthly counts  between July 1995 and December 2003. A binary dummy variable indicat- ing  whether  the  IBIS  technology  was  present  or  not  was  constructed  to  estimate the effects of the intervention on the monthly counts of cold hits.  Negative  binomial  regression  models,  controlling  for  the  monthly  count  of  gun  crimes,  seasonal  variations  as  measured  by  monthly  dummy  vari- ables, and simple linear and nonlinear trends, revealed that  the  adoption  TAbLE A-1  Staffing Levels of the Boston Police Department Ballistics  Unit, 1993–2003 Year Supervisors Firearms Examiners Support Staff Total 1993 1 7 1 9 1994 1 7 1 9 1995 1 7 1 9 1996 2 7 1 10 1997 2 6 2 10 1998 2 5 3 10 1999 2 6 3 11 2000 2 5 3 10 2001 2 5 3 10 2002 1 4 4 9 2003 1 5 5 11

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0 APPENDIX A of IBIS was associated with a statistically significant six-fold increase in the  monthly number of hits generated by the BPD ballistics unit.5 Some  observers  suggest  that  ability  of  IBIS  technology  to  make  links  across crime scenes can be easily undermined by criminal offenders. These  critics  suggest  that  ballistic  imaging  technology  is  limited  because  deter- mined criminals can alter markings on or replace barrels, slides, extractors,  and  firing  pins.  These  modifications  would  alter  the  telltale  markings  on  ballistics evidence and prevent matches from being made (see, e.g., Kopel  and  Burnett,  2003).  Unfortunately,  data  are  not  available  to  determine  whether criminals are modifying their firearms to avoid detection. However,  if  criminals  are  seeking  to  avoid  detection,  they  can  simply  switch  from  semiautomatic pistols to revolvers because the latter are less likely to leave  cartridge  casings  at  a  scene  when  fired.  The  available  evidence  suggests  that  Boston  gun  criminals  are  not  switching  guns  to  avoid  detection:  As  Figure A-4 shows, there was no substantive change in the proportions of  semiautomatic pistols and revolvers in handguns recovered by the Boston  Police after the adoption of IBIS in 1995. Extended Analyses of boston IbIS Matches The Boston Police Department’s Unsolved Shootings Project and Impact  Player Assessment meetings held between October 2001 and July 2004 gen- erated detailed data on gun crime incidents and gun criminals involved in  IBIS matches. A total of 104 sets of ballistics matches involving 244 distinct  gun  crimes  were  made  over  the  course  of  this  initiative.6  The  number  of  incidents in each set of matches ranged from 2 gun crimes to 6 gun crimes  with  a  mean  of  2.3  gun  crimes  per  set.  The  amount  of  time  between  the  first incident and the last incident in a set of ballistics matches ranged from  a  few  hours  to  34  months,  with  a  mean  of  6  months.  Five  calibers,  all  of  which  are  commonly  used  in  semiautomatic  pistols,  accounted  for  93  percent of the crime guns used in these 104 sets of IBIS matches. The five  most frequently matched calibers were 9mm (39 percent), .38 (21 percent),  .40 (12 percent), .45 (11 percent), and .25 (10 percent). The 244 gun crime  incidents included in the 104 sets of matches mostly involved gun assaults  5  In  this  updated  analysis,  the  findings  are  essentially  unchanged  from  the  original  (see  Braga  and  Pierce,  2004)  study.  The  key  coefficients  in  the  updated  negative  binomial    egression  model  were  IRR  =  6.0988,  Robust  SE  =  2.4723,  Z  =  4.46,  P>|Z|  =  0.000,  and  r log likelilhood = –314.0913. 6  he  term  “set  of  matches”  is  used  to  distinguish  the  matches  discussed  here  from  those  T discussed above: A set of matches involves all hits (or matches) generated by the same gun  across multiple crime scenes; a match, as used above, simply is a hit based on new evidence  entered into IBIS. 

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0 BALLISTIC IMAGING 100 90 Revolvers Semiautomatics 80 70 Percentage 60 50 40 30 20 10 0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year FIguRE A-4 Recovered handguns in Boston, 1991–2003. A-4.eps (43 percent), shots fired (30 percent), and illegal gun possession (13.5 per- cent) cases; see Table A-2. An arrest was associated with 51 percent of the match sets (53 of 104)  resulting in 87 individuals arrested. An analysis of the timing of the arrests  suggests a complex investigative process. In 52.8 percent of the match sets,  the arrest and the last incident coincided. In these cases, the arrest of the  gun offender(s) seemed to end the chain of violent events that was associ- ated with a particular crime gun. In 32.1 percent of the match sets, an arrest  was  made  after  the  last  incident.  This  time  lag  suggests  that  additional  investigative  work  led  to  the  identification  and  eventual  apprehension  of  the gun criminal(s) involved in a string of incidents using the same gun. At  least one additional gun crime was committed with the same gun after an  offender was arrested in 15.1 percent of the sets of matches. This situation  suggests that, although an offender was apprehended, the crime gun was  still on the street and being used in subsequent crimes.  As  described  above,  IBIS  matches  do  not  change  the  inherent  value  of ballistics evidence in an investigation because many  other factors help  determine  whether  an  arrest  is  eventually  made.  An  IBIS  match  does  not  guarantee an immediate arrest. For instance, the linked incidents may not  involve victims or witnesses that can or are willing to make a positive iden-

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0 APPENDIX A TAbLE A-2  Crime Types in 104 Sets of Boston IBIS-Suggested Matches Crime Type Number Percent Gun assault 104 42.6 Shots fired 72 29.5 Illegal gun possession 33 13.5 Gun homicide 17 7.0 Warrant (search/arrest) 13 7.0 Found gun 4 1.6 Gun robbery 1 0.4 tification. Rather, matches better position law enforcement agents to iden- tify gun criminals through strategic analyses of information and intelligence  sharing. The Boston Police and their criminal justice partners use the IBIS  information as a tool to shed light on the dynamics at play in violent street  social networks and further their ability to apprehend violent gun criminals.  IBIS provides Boston investigators with more opportunities to make links  among individuals and locations through a particular gun. The IBIS matches were associated with the arrest of very serious gun  offenders that were well known to the criminal justice system. Of the 87  arrested gun offenders associated with the IBIS matches, 93 percent were  male, and they ranged in age from 13 to 51 years, with a mean of 22 years  of age. When the names and birth dates of these arrest individuals were run  through Massachusetts state criminal history systems, 92 percent had been  arraigned at least once in Massachusetts courts prior to their current arrest.  Of  these  known  offenders,  59  percent  were  previously  convicted  felons  and, after their personal information was run through the BPD intelligence  database  system,  42  percent  were  known  gang  members.  Of  the  known  o   ffenders, they had a mean of 10 prior arraignments for a wide variety of  criminal  offenses:  63  percent  had  at  least  one  prior  armed  violent  crime  arraignment,  51  percent  had  at  least  one  prior  unarmed  violent  arraign- ment, 36 percent had at least one prior nonviolent gun crime arraignment,  60  percent  had  at  least  one  prior  drug  crime  arraignment,  75  percent  had at least one prior property crime arraignment, and 75 percent had at  least one prior disorder crime arraignment. These gun offenders were also  extensively involved with the criminal justice system before their immedi- ate arrest. Of the previously known offenders, 48 percent were on active  probation when they were arrested, 83 percent were on probation prior to  their arrest, 64 percent had been committed to a secure adult or juvenile  correctional facility prior to their arrest, and 15 percent had been subjected  to a restraining order before their arrest.

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0 BALLISTIC IMAGING High  conviction  rates  for  fully  adjudicated  gun  offenders  were  also  associated  with  the  IBIS  matches.  It  is  important  to  note  again  that  IBIS  matches do not guarantee or necessarily generate a conviction. Rather, in  Boston, IBIS data are one part of an aggressive investigative process that is  highly focused on sharing information and analyzing data to apprehend vio- lent gun offenders. As such, the higher conviction rates should be credited  to the overall law enforcement initiative rather than simply being credited  to IBIS matches. In November 2004, 58.6 percent of the arrested offenders  were fully adjudicated, 34.5 percent were still engaged in the trial process,  and 6.9 percent were not charged for their crimes. Of the fully adjudicated  offenders,  76.5  percent  were  convicted  of  their  current  gun  crime.  These  convicted offenders were usually sentenced to incarceration (87.2 percent),  with sentences ranging from 6 to 120 months (mean, 32 months; median,  18 months; mode, 12 months). The  arrested  offenders  associated  with  the  IBIS  matches  were  more  serious offenders than 514 adults arrested for homicide, gun assault, gun  robbery, and illegal gun possession in Boston in 1995.7 Of these offenders,  76 percent had been arraigned in Massachusetts courts at least once before  their  current  gun  crime  arrest;  37  percent  of  these  known  offenders  had  prior  felony  convictions.  The  IBIS  offenders  were  also  more  likely  to  be  convicted of their gun crimes than the 1995 cohort of Boston gun offenders  who had a 37 percent conviction rate for past armed violent felonies and  gun possession offenses. The use of IbIS Matches in gun Enforcement Operations To  further  document  the  use  of  IBIS  matches  in  Boston’s  interagency  gun violence prevention efforts, available official data associated with 44  IBIS  matches  made  by  the  BPD  ballistics  unit  in  2003  (incident  reports,  arrest  reports,  intelligence  reports,  ATF  trace  data)  were  collected  and  analyzed. These data were presented to the Boston Police investigators and  S   uffolk  County  assistant  district  attorneys  who  participated  in  the  inter- agency working group meetings during 2003. The use of the 44 matches  in their gun violence prevention activities was discussed in a series of inter- views and focus group sessions. The 44 matches linked 108 incidents (mean of 2.5 incidents per match,  range  2–8  incidents).  Collectively,  59  victims  and  28  arrested  individuals  were  involved  in  the  108  incidents.  The  presence  of  offenders,  victims,  and  witnesses  to  interview  about  the  gun  crime  varied  across  the  events:  7  These  data  were  collected  as  part  of  an  unpublished  study  of  gun  offender  criminal  his- tories in Boston and other cities and are available on request from Anthony Braga (see also  Braga, 2003).

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0 APPENDIX A 75 percent of the matches (33) had victims associated with at least one of  the linked incidents; 59.1 percent of the matches (26) had arrested offend- ers  associated  with  at  least  one  of  the  linked  incidents;  18.2  percent  of  the matches (8) did not have witnesses for any of the linked crime scenes.  Crime scenes that did not have any witnesses were linked to crime scenes  that did have witnesses in 47.7 percent of the matches (21). In 34.1 percent  of  the  matches  (15),  witnesses  were  available  at  all  linked  crime  scenes.  Guns  were  recovered  in  25  of  the  44  matches  (58.8  percent):  13  of  the  25 guns (52.0 percent) were traced by ATF to the first retail purchaser; 11  (25 percent)  matches  involved  a  link  to  a  homicide  incident  (one  linked  two homicides). The investigators and prosecutors strongly believe that all IBIS matches  added general investigative and intelligence value to their operations. How- ever,  not  all  matches  linked  information  that  resulted  in  significant  addi- tional  investigative  activity.  Matches  involving  homicide  incidents  were  more likely to generate significant investigative leads when separated from  the pool of 44 matches. Homicides are more vigorously investigated than  shots  fired  and  gun  assaults  incidents  and,  generally,  have  more  evidence  that can be linked to other events (such as a victim with a known criminal  history).  IBIS  matches  did  not  generate  any  direct  enforcement  actions  in  61.4  percent  of  the  44  matches  and  27.3  percent  of  the  11  homicide  matches; see Table A-3. Offenders were charged with the current offense  only  and  not  charged  with  a  linked  prior  gun  crime  in  34.1  percent  of  the 44 matches. In the two matches linking homicides, the offenders were  TAbLE A-3  Results of Information Linked by IBIS-Suggested Matches on  Investigations by Boston Law Enforcement Agencies, 2003 All   Homicide  Matches Matches Direct Enforcement Actions (N = 44) (N = 11) No direct enforcement action; IBIS-suggested match only had  27 3 general investigative and intelligence value Arrest based on current offense, no potential for additional charges  15 2 in linked crimes No arrests and no potential for immediate charges based on linked  12 1 information Significant investigative lead generated by IBIS match 17 8 Arrest made or arrest warrant issued as a result of linked  8 4 information Suspects identified; however, charges not filed because linked  8 3 evidence was not strong enough Case resolved as homicide victim had gun used in prior homicide 1 1

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0 BALLISTIC IMAGING interviewed about a prior linked gun crime, but only charged in the sub- sequent  homicide  incident.  Of  the  matches,  27.3  percent  did  not  have  arrests  for  current  offenses  or  any  immediate  potential  for  charges  based  on linked information. In the one homicide match included in this category,  the unsolved homicide was linked to a shots fired incident with no arrests,  victims, or witnesses to interview. IBIS matches generated significant investigative leads in 38.6 percent of  the 44 matches and 72.7 percent of the 11 homicide matches. The linked  information resulted in an arrest or an arrest warrant in 18.2 percent of the  44 matches and 36.4 percent of the 11 homicide matches. Unfortunately,  linked information across crime scenes can be highly suggestive of the iden- tity of a violent gun offender but not sufficient enough to support formal  charges. In 18.2 percent of the 44 matches and 27.3 percent of the homicide  incidents, likely suspects were identified and interviewed but not charged  because the information chain connecting the events was not strong enough  to justify an arrest. In one case, a homicide investigation was resolved but  an arrest was not made because the ballistics link was made from a test fire  of the gun recovered from a homicide victim who was a suspect in a prior  homicide incident.  While  all  matches  were  regarded  as  valuable  by  the  interviewed  law  enforcement agents, the matches that led to an arrest clearly added the most  value  to  gun  violence  prevention  strategies.  The  2003  investigation  and  arrest  of  a  homicide  suspect—for  anonymity,  referred  to  as  A—provides  a good example of the usefulness of links between crime scenes made by  IBIS matches. The Boston Police were conducting a surveillance of a known  crack-cocaine  drug  market  location  in  the  city.  The  police  witnessed  an  apparent drug transaction and, after interviewing the suspected customer,  they attempted to interview A and B, the suspected sellers. A immediately  fled  and  fired  at  least  one  shot  at  the  pursuing  officers.  After  a  standoff,  A  surrendered  and  was  arrested  on  assault,  firearm,  and  drug  charges;  a  Glock semiautomatic pistol was recovered. During booking, Boston Police  officers recovered receipts from A documenting the purchase of the Glock  pistol by another person from an out-of-state federal firearms licensee. The  Glock  was  test  fired,  and  the  resulting  cartridge  casing  was  entered  into  IBIS. After the automated correlation and a microscopic comparison by a  firearms examiner, the casing was matched to a cartridge casing recovered  at the scene of a homicide in 2002. Witnesses were present at the time of the  homicide but were not able to provide a detailed description of the assail- ant. Further investigation revealed an ongoing personal feud between A and  the homicide victim. As a direct result of the IBIS match, A was charged  with murder; A was subsequently convicted and is serving a life sentence  for murder in the first degree.

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0 APPENDIX A Estimating the Costs and benefits of IbIS Braga  and  Pierce  (2004)  estimated  the  cost-effectiveness  of  the  IBIS  technology in making ballistics matches in two ways: the cost of making a  match and the cost of comparing a piece of ballistics evidence to the exist- ing  inventory  of  evidence.  In  1995,  the  IBIS  equipment  used  by  the  BPD  was purchased by ATF at a cost of $540,000. Reflecting general trends in  decreasing technology costs, the same equipment cost $295,000 in Decem- ber  2003.  As  of  December  31,  2003,  the  BPD  ballistics  unit  had  made  a  total  of  404  cold  hit  matches  involving  cartridge  casings  using  the  IBIS  technology. Using 2003 prices, the equipment costs amount to $730.20 per  cartridge casing match.8 There are two reasons to believe that this cost estimate will continue to  decrease markedly as time progresses: (1) as more evidence is entered into  IBIS, the probability of making a hit will increase and the absolute number  of hits will continue to increase; (2) as with the costs of other computer- related technologies, the cost of the IBIS technology will also decline over  time. As Table A-1 (above) documents, the addition of the IBIS equipment  did not result in new hires by the BPD to staff the ballistics unit. Except for  some time invested in training staff to properly operate the IBIS equipment,  the direct annual cost to the BPD is zero. The ATF costs can be amortized  on an annual basis over the course of the lifetime of the equipment. Importantly,  IBIS  can  routinely  scan  vast  inventories  of  ballistics  evi- dence in a manner that was for most practical purposes impossible prior  to  the  availability  of  this  technology.  IBIS  technology  allows  each  newly  entered piece of ballistics evidence to be compared against existing inven- tories that can easily reach thousands in a matter of minutes. Before IBIS,  making  cold  hits  was  an  ad  hoc  process  that  was  limited  by  the  ability  of  firearms  examiners  to  compare  selected  cartridge  casings  to  the  larger  inventory of crime scene casings in the property of the ballistics unit. For  example, in September 1993, Detective John Mulligan was shot, execution  style, five times in the head with a .25 caliber firearm as he sat in his car  while working as a private security detail at a Walgreens pharmacy in the  Roslindale neighborhood of Boston (Braga and Pierce, 2004). In an attempt  to develop more information on the case, the BPD selected 50 .25 cartridge  casings from recent violent crimes in the surrounding neighborhood. Five  8  his represents an update over Braga and Pierce (2004), who reported a cost of $744 per  T match based on 396 matches made through early December 2003. However, either estimate  is far lower than the cost estimates of $12,000 per cartridge case hit suggested by Kopel and  Burnett (2003). The difference in estimates is the result of comparing IBIS in one jurisdiction  (Boston) that has been operating comprehensively for a number of years to an aggregate of 222  systems across the United States, some of which received the technology only a few months  before the Kopel and Burnett report and were not yet fully operational.

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0 BALLISTIC IMAGING firearms examiners spent 10 8-hour days comparing the selected casings to  the recovered crime scene evidence (Braga and Pierce, 2004). Unfortunately,  this intensive effort did not result in a match.9   Braga  and  Pierce  (2004)  used  this  anecdote  as  an  opportunity  to  estimate  the  cost  of  comparing  one  cartridge  casing  to  the  BPD’s  inven- tory  of  cartridge  casings.  In  December  2003,  the  average  BPD  firearms  examiner earned $50,000 per year. As such, the BPD would pay one fire- arms examiner $2,083.33 to work 10 days. Five firearms examiners would  cost $10,416.67 for the same time period. As the story describes, the five  examiners compared 50 casings to one piece of evidence during this time  period. Therefore, it cost the BPD $208.33 to compare two cartridge cas- ings. Assuming the BPD had unlimited resources and firearms examiners,  it would cost more than $2.6 million to compare one cartridge casing to  every one of the more than 12,700 cartridge casings in the BPD’s inventory  as of December 2003. Braga and Pierce (2004) observe that these figures  were not meant to be precise estimates; rather, they simply illustrate that  the cost of human examiners routinely scanning existing ballistics evidence  inventories  for  likely  matches  is  prohibitive,  and  even  this  assumes  that  human resources are available to make such comparisons. In contrast, the  cost  of  routinely  scanning  existing  ballistics  evidence  inventories  to  find  potential matches, using IBIS equipment is modest.  It is important to note, however, that these cost-effectiveness estimates  were calculated on basis of the performance of IBIS in matching cartridge  casings. IBIS technology is not as cost-effective in making ballistics matches  with recovered bullet evidence. Between 1995 and 2003, the Boston Police  only made eight cold hit bullet matches. Using 2003 prices, the equipment  costs amounts to $36,875 per bullet match.10 The benefits of IBIS to gun enforcement operations can also be assessed  by  estimating  the  number  of  arrests  resulting  from  IBIS  matches  to  the  number of arrests that would have been made from traditional methods of  making  cold  hits  if  the  IBIS  technology  had  not  been  available.  In  2003,  18.2  percent  of  IBIS  matches  resulted  in  an  arrest  or  the  issuance  of  an  arrest warrant for a linked gun crime. Since IBIS was adopted in 1995, 412  matches were made by the end of 2003. Using 2003 figures as a reasonable  basis to estimate the role of IBIS in making arrests, 75 (18.2 percent of 412)  matches  would  have  generated  an  arrest.  If  IBIS  had  not  been  available,  traditional ballistics methods would have yielded about 81 total matches  between  1995  and  2003  (8.8  per  year  multiplied  by  9  years)  and  about  9  he two suspected killers were arrested after the .25 handgun was found in a vacant lot  T some 100 yards from the home of one of the suspects in the Dorchester section of Boston. 10  This  figure  is  still  much  lower  than  the  $195,000  per  bullet  hit  estimate  suggested  by  Kopel and Burnett (2003).

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09 APPENDIX A 15 would have yielded arrests for linked gun crimes (18.2 percent of 81).  Therefore, IBIS can be associated with making arrests in an additional 60  linked gun crimes—4.4 times as many arrests for linked gun crimes—when  compared with the performance of traditional ballistics methods. CONCLuSION The capabilities and cost advantages provided by IBIS technology can  significantly  increase  the  use  of  ballistics  evidence  by  law  enforcement.  B   allistics  matches  made  by  IBIS  are  an  important  part  of  Boston’s  inter- agency efforts to prevent gun violence. According to Boston law enforce- ment agencies, all matches have strategic value in understanding ongoing  violent conflicts among gangs and criminally active groups that are major  parts of the city’s violence problem. The IBIS matches, and the information  chains that result from the linked gun crimes, are used to mount investiga- tions of suspected violent gun criminals and to develop and implement vio- lence reduction strategies to prevent additional gun crimes from happening.  The BPD further asserts that the ability of IBIS to make quick comparisons  to  a  large  inventory  of  ballistics  evidence  has  yielded  a  number  of  high- profile  investigations  that  would  not  otherwise  have  been  possible.  For  example, in 2000, a 9mm handgun was matched to 15 other gun crimes  in Boston, Brockton (MA), Randolph (MA), and Providence (RI) (NIBIN  Program, 2001). Boston IBIS matches, coupled with an interagency focus  on  apprehending  and  prosecuting  violent  criminals  by  all  available  law  enforcement means, were also associated with the arrest of very serious gun  offenders and high conviction rates for their immediate gun offenses.  The  results  of  this  research  study  suggest  that  the  IBIS  technology  significantly increased the productivity of the BPD ballistics unit in linking  guns crimes. The analysis found that the adoption of the IBIS technology  was  associated  with  a  more  than  six-fold  increase  in  the  number  of  cold  hit matches per month. Clearly, the IBIS technology significantly increases  the ability of law enforcement agencies to make ballistics matches across  crime scenes. The cost-effectiveness estimates and qualitative evidence also  suggests that the IBIS technology allows law enforcement agencies to make  hits that would have otherwise not been possible. Before IBIS was adopted  by  the  BPD,  ballistics  matching  across  gun  crime  scenes  was  an  ad  hoc  and tedious process. Now, the BPD can systematically compare recovered  gun  crime  evidence  to  its  entire  inventory  of  evidence  with  little  effort.  The unfortunate 1993 Boston police officer execution-style slaying and the  well-known 2000 investigation involving one firearm used in 15 separate  incidents provide stark contrasts in the ability of the BPD to link the use of  firearms across gun crime scenes. The  experience  of  the  BPD  indicates  that  the  use  of  IBIS  technology 

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0 BALLISTIC IMAGING should be accompanied by a department-wide commitment to comprehen- sively image all ballistics evidence collected by a law enforcement agency.  Without  such  a  commitment,  one  of  the  major  advantages  of  IBIS,  the  ability  to  routinely  scan  large  inventories  of  evidence  for  potential  links,  is  obviously  reduced.  Using  the  Boston  experience  as  a  model,  the  U.S.  Attorney’s Office in the District of Massachusetts has collaborated with the  Massachusetts State Police to set up a process for collecting and analyzing  ballistics evidence to aid gun law enforcement operations in 11 target cities  for  the  U.S.  Department  of  Justice  Project  Safe  Neighborhood  initiative.  The  Massachusetts  U.S.  Attorney’s  Office  provides  the  state  police  with  $35,000 per year to support the overtime that is necessary to ensure timely  ballistic imaging at the state crime laboratory. The steps of this process are  as follows: •  Local evidence collection: Participating police agencies must collect  all evidence at gun crime scenes, which includes the collection of crime gun  evidence at shots fired scenes where no injuries or fatalities are reported. •  Transfer  to  evidence  officer:  Once  the  crime  scene  ballistics  evi- dence is collected, it must be immediately transferred to the department’s  evidence officer. •  Transfer  to  Massachusetts  State  Police:  The  evidence  officer  must  immediately  submit  the  ballistics  evidence  to  the  state  police  crime  laboratory. •  Timely  ballistics  examination:  The  state  police  must  immediately  image  the  crime  scene  evidence  and  determine  whether  a  match  exists  within its inventory of ballistic image evidence. •  Report to investigators: The results of ballistics examination are to  be communicated by state police firearms examiners to investigators from  the submitting agency as soon as available. •  Report to gang unit: The results of the ballistics examination are  to be shared with relevant units within the police department, such as the  gang unit, to see if additional information can be developed on the loca- tions, individuals, and crime gun involved in the match. •  Report to prosecutors: The information must be shared with fed- eral and local prosecutors to coordinate priority prosecutions. •  Regional  or  statewide  analysis:  Because  violent  criminals  some- times cross jurisdictional boundaries, ballistics evidence is to be analyzed  at larger levels of aggregation beyond the city where the immediate offense  occurred.  In contrast to state-level systems that image guns not involved in crime  (for a critique, see Kopel and Burnett, 2003), ballistic imaging systems that  are built on comprehensive imaging of all recovered gun crime evidence and 

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 APPENDIX A supplemented  by  strategic  data  analyses  and  intelligence  gathering  seem  to show great promise in apprehending violent gun criminals. The Boston  experience with ballistic imaging technology suggest that ATF’s NIBIN pro- gram, with appropriate support, can ensure that participating jurisdictions  are well trained in the practices of comprehensive ballistic imaging.