Why do gun murders have a higher clearance rate than gunshot assaults?

Abstract

Research Summary The prevailing view is that follow‐up investigations are of limited value as crimes are primarily cleared by patrol officers making on‐scene arrests and through the presence of eyewitnesses and forensic evidence at the initial crime scene. We use a quasi‐experimental design to compare investigative resources invested in clearing gun homicide cases relative to nonfatal gun assaults in Boston. We find the large gap in clearances (43% for gun murders vs. 19% for nonfatal gun assaults) is primarily a result of sustained investigative effort in homicide cases made after the first 2 days. Policy Implications Police departments should invest additional resources in the investigation of nonfatal gun assaults. When additional investigative effort is expended, law enforcement improves its success in gaining the cooperation of key witnesses and increases the amount of forensic evidence collected and analyzed. In turn, the capacity of the police to hold violent gun offenders accountable, deliver justice to victims, and prevent future gun attacks is enhanced.

Improving police effectiveness in ensuring justice

“…Together, in this set of studies (Cook, Braga, Turchan, & Barao, ; Eck & Rossmo, ; Wellford, Lum, Scott, Vovak, & Scherer, ), these scholars suggest that considerable progress could be made in improving the effectiveness of criminal investigation if more focus were placed on investing resources in figuring out what may work in different organizational contexts. We have now accumulated some indication that evidence collected soon after the case occurred is essential, that devoting more resources and investigators to cases, potentially in teams, will lead to higher clearances.…”

“…Philip Cook, Anthony Braga, Brandon Turchan, and Lisa Barao (, p. 525) provide an example of this new body of evidence, showing that investigative effort matters in increasing the chance that a shooting case is cleared by an arrest. This article challenges the prevailing view that follow‐up investigations are “clerical work” that provide limited value in clearing a homicide by presenting evidence from a quasi‐experimental design that compares resources devoted to clearing homicide cases involving guns with nonfatal gun assaults in Boston.…”

“Oh hell no, we don't talk to police”

“…Therefore, disarmament is more unlikely in ecological contexts where firearm violence is pervasive and individuals seemingly strike with impunity. We recommend that city leaders allocate additional resources to police units responsible for investigating nonfatal shootings in an effort to make high‐risk places demonstrably safer (Cook et al., , p. 525). This is a worthwhile investment because not only do nonfatal incidents represent most shootings, but they also consistently produce untold residual violence, fear, and disorder, collectively undercutting police effectiveness.…”

Clearing homicides

“…The analysis needed here, however, is not only on the time to resolution but also on the various typologies of investigative efforts for various classifications of the resolution potential of homicide cases. New metrics of investigative efforts beyond those used here should be developed in future studies to advance this work (see Cook, Braga, Turchan, & Barao, , p. 525).…”