staff, August 21, 2015

As headlines in cities across the United States highlight rising death tolls caused by open gang warfare in the streets, pundits, politicians and community leaders have put forward various legal and law enforcement solutions in order to alleviate this growing problem.

But what if this issue can?t be resolved by the cops and the courts? A team at Michigan State recently offered a different perspective when it published findings of a study that showed how gang violence spreads in the same fashion as a contagion.

MichiganState_gangs2?The idea that some types of homicide can be contagious has been around since the 1980s,? said April Zeoli, an associate professor of criminal justice. ?But we are the first researchers to show it moves through space and time like an infectious disease. The idea had been there, but we were the first to show it (that way.)?

The report is based on an examination of crime records in Newark, N.J., where gang slayings were found to move in a systematic pattern.

?It?s incredibly alarming,? she said the research findings. ?Gang homicide is a big problem right now in Newark, and any time you have people being killed is alarming. We are doing a follow-up study to find out why gang homicides move to one area and not others.?

This map from MSU shows the spread of gang violence in Newark over time.
This map from MSU shows the spread of gang violence in Newark over time.

Zeoli said she and her research team aimed their study at Newark because Jesenia Pizarro, a criminologist in Michigan State?s School of Criminal Justice, is from that city. Newark ranks near the top of the list of large U.S. cities with the high rates of murder and other violent crimes, according to recent FBI crime reports.

?She had relationships with police and got the [crime] records,? Zeoli said.

Data from the Newark Police Department Homicide Unit?s investigative files from 1997-2007 shows homicide spreading in a pattern that eerily resembles a human illness, such as the flu.

?Gang-motivated homicides showed evidence of clustering and diffusion through Newark,? the researchers wrote in the study. ?Additionally, gang-motivated homicide clusters overlapped to a degree with revenge and drug-motivated homicide clusters. Escalating dispute and nonintimate familial homicides clustered; however, there was no evidence of diffusion. Intimate partner and robbery homicides did not cluster.?

Zeoli said the infectious disease model of homicide is based on three significant factors.

?For a disease to spread, there first needs to be a source like germs or infection,? Zeoli said. ?You need conditions where interactions will lead to a homicide. Firearms, drug markets and gang members can be sources.

?Second, there need to be a mode of transmission for homicide,? she added. ?It can be word-of-mouth. If a guy hears a fellow gang member has been killed, it can be spread.?

Fear also can be a factor in helping homicide spread, according to Zeoli.

?It could be more dangerous if people in fear are carrying guns,? Zeoli said. ?They appear strong and not to be messed with, but these behaviors - though people are using them to protect themselves - could lead to more violence. It ups the ante.?

Finally, the spread of homicide in terms of a disease requires a population based that is ?susceptible? to violence, according to Zeoli.

[btn-post-package]?People who live in economically disadvantaged communities might feel unprotected by law enforcement and use homicide for social control,? she said. ?These three things are analogous for disease to spread and gang violence has all those elements.?

Zeoli said the focus of ongoing studies on gang homicide might uncover concrete ways to prevent and intervene with the spread of violent activity.

?We?re trying to get at the root causes why gang homicides spread,? Zeoli said. ?If we can figure that out, we can move on to prevention.?

By Tony Moton