Gang-related homicides follow a specific pattern, study finds


In research that they believe could help prevent these violent crimes in the future, criminologists at Michigan State University have discovered that gang slayings move in a systematic pattern over time, spreading like a disease from one vulnerable area to another.

Their findings, which have been published online in the American Journal of Public Health, found that there is “a potentially systematic movement of gang-related homicides,” lead author and MSU associate professor of criminal justice April Zeoli explained in a statement.

“Not only that, but in the places gang homicides move into, we see other types of homicide – specifically, revenge and drug-related killings – also clustering. Taken together, this provides one piece of the puzzle that may allow us to start forecasting where homicide is going to be the worst – and that may be preceded in large part by changes in gang networks,” she added.

Zeoli previously was also a member of the MSU team that, in 2012, reported that homicide as a whole spreads through cities like infectious disease. They applied public health tracking methods to more than 2,300 homicides from 1982 through 2008, and discovered that murders followed a pattern, starting in the center of a city, then spreads to the south and west.

Tracking different types of murder in Newark

Using police data from Newark, New Jersey, the study authors reported that like diseases, homicide needs a susceptible population, an infectious agent, and a vector in order to spread. The infectious agent could be street code (protecting one’s reputation by all costs, including violence) while the vector could be word-of-mouth publicity.

As part of the new study, Zeoli’s team once again analyzed data from Newark to see if specific types of homicides cluster and spread differently. Along with gang-related murders, they looked at revenge killings and homicides linked to domestic violence, robbery, and drugs. As it turns out, each different type of homicide does, in fact, have a different pattern.

Deaths linked to domestic violence and robberies showed no signs of clustering or spreading out, the study authors found, and while revenge and drug-motivated homicides unrelated to gangs did not spread out, they did tend to cluster – often in the same area as the gang activity.

Gang-related murders were the only ones found to spread out in a specific pattern, as they found four contiguous clusters that started in central Newark and moved in a roughly clockwise pattern from July 2002 through December 2005. The authors wrote that tracking how different homicide types spread through a community can improve prevention and intervention efforts.

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