Researchers at Duke University and Northeastern University have found a stark gap in clearance rates when comparing fatal and nonfatal gun assaults in Boston.
In the study, published in the latest edition of Criminology & Public Policy, a journal of the American Society of Criminology, the researchers found that between 2010 and 2014, Boston police solved 43 percent of gun murder cases—but only 19 percent of nonfatal gun assaults.
Fatal and nonfatal gunshot assaults are nearly indistinguishable with respect to victim characteristics and circumstances, the researchers pointed out. In both cases, investigators face a complicated crime scene: detectives have to comb the area for bullets fired, determine the kind of weapon used, identify suspects and eyewitnesses, and collect DNA.
According to the study, the gap in clearance rates is, “…primarily a result of sustained investigative effort in homicide cases made after the first two days,” compared to a lack thereof when a victim survived the attack.
The Boston Police Department (BPD) considers cases “cleared” if there is at least one arrest or, “in exceptional cases, if the BPD has identified a suspect who cannot be arrested.”
Those “exceptional” cleared cases are typically when the main suspect has died.
But there’s no industry standard on when a case should be “cleared,” the study said.
As soon as possible is always preferable; but when comparing arrest times, researchers found “between two days and six months, there is an arrest in 20 percent of the fatal cases but in only 6 percent of the nonfatals.”
An additional 12 percent of fatal cases are solved after six months, but only 2 percent of nonfatal cases are cleared, the study found.
According to the researchers, their findings prove that investigators are putting more effort into solving the fatal gunshot assaults compared to the nonfatal ones.
The research is borne out by other data.
In an analysis of homicide reports and FBI Incident-Based data sets published earlier this year by The Trace and Buzzfeed News, researchers found that the cities of Los Angeles, Chicago, and Las Vegas each had arrest rates below 20 percent for gun assaults.
After receiving internal data from 22 police departments, The Trace also found that, “San Francisco had a lower arrest rate than Newark, New Jersey — a city with nearly six times the number of shootings per capita.”
The study, entitled “Why do gun murders have a higher clearance rate than gunshot assaults?” found that another reason a fatal shooting would get cleared faster than a nonfatal one is the fact that more evidence is collected in homicide cases compared to nonfatal cases.
However, given that these kinds of cases are similar, “the higher success rate in homicide investigations is closely linked to greater effort in gathering and processing forensic evidence.”
Homicide crimes also result in subsequent forensic tests that don’t always take place after nonfatal shootings.
The Boston Police Department reported that ballistic evidence was sent to a lab for further testing in 14 percent of 200 cases, whereas only 5 percent of 228 nonfatal shootings had Ballistics Evidence examined. The same trends can be seen for video evidence, latent prints, and mobile phone evidence when comparing the two kinds of shootings.
The study authors reported that when they asked detectives about which evidence was key to identifying a suspect, a majority of the answers related to interviewing witnesses. Citizen cooperation is key, and they noted “…a much higher likelihood of cooperation by a key witness in fatal than in nonfatal cases.”
It is also especially noteworthy that the “median number of post-scene witnesses interviewed in homicide cases is two, and for nonfatal cases, it is zero.”
So, even though gathering an eyewitness account of a crime taking place is incredibly important, police officers sometimes failed to interview anyone for nonfatal gunshot incidents.
Based on their findings, the researchers argued for policy changes in police agencies relating to the investigations of gun assault cases.
A key recommendation was to earmark resources for the investigations of nonfatal gun assaults to match the efforts put into fatal investigations.
That would improve police-community relations, according to the study, since local residents will feel more confidence in law enforcement’s willingness to investigate all crimes.
By treating nonfatal gun cases with the same severity and intensity as fatal gun incidents, the researchers argue police departments may see increases in their clearance rates, prevent future gun attacks, and help deliver justice to victims.
The co-authors of the study were Philip J. Cook of Duke University; and Anthony A. Braga, Brandon S. Turchan, and Lisa M. Barao, all of Northeastern University.
It was supported by funds from provided by the U.S. Bureau of Justice Assistance and the Rappaport Institute for Greater Boston.
The full article is available here.