This study shows a link between those who murdered in Newark, NJ and looked at them like an infectious disease.
While the study may have been extensive, it does not seem quite conclusive. They looked at murders that occured between 1982 and 2007 which totaled over 2,000. They looked at the time and location of each murder and used a software to calculate the data. I'm just not sure the use of the software can always be trusted.
Click this link to LISTEN to the story, and read more.