How A Computer Algorithm Could Help Police Track A Possible Serial Killer In Chicago

NPR's Ailsa Chang talks with Thomas Hargrove, founder of the Murder Accountability Project, about the algorithm he created to track a possible serial killer in Chicago.

AILSA CHANG, HOST:

The FBI is investigating the possibility of a serial killer in Chicago. In a joint investigation with the city's police force, authorities are looking into 51 unsolved murders on the South and West Sides. Most of the victims have been African-American women, many of them sex workers. And all of them were strangled or asphyxiated.

Thomas Hargrove is the founder of the Murder Accountability Project. He created a computer algorithm to uncover patterns in homicides across the country, and he's here to talk about it today. Welcome.

THOMAS HARGROVE: Thank you for having me.

CHANG: So what first grabbed your attention about these homicides in Chicago?

HARGROVE: Well, America, unfortunately, is a pretty violent place.

CHANG: Yeah.

HARGROVE: We usually are having about 17,000 murders a year. It's a little hard to keep track of it all. But a computer model can go through all of those records and look for patterns that might be of interest to police.

CHANG: And what are the common threads your model saw in these killings that caused you to conclude that maybe some of them could be the work of a serial killer?

HARGROVE: The algorithm alerted us that there is a pattern of unsolved murders amongst women who were asphyxiated or strangled.

CHANG: OK.

HARGROVE: Seventy-four percent of those murders were not being solved. That's pretty unusual. But when we put names and description of the nature of the murder, that's when it became really quite stark. The common M.O. in these murders are really dramatic. Almost all of these women were recovered out of doors - 94 percent.

CHANG: Of their bodies were found outside or in abandoned buildings.

HARGROVE: Right - alleyways, abandoned buildings, open lots. Murder tends to be an indoor sport, but these cases were entirely out of doors. Also, there were frequently signs of sexual activity - not necessarily voluntary activity.

CHANG: Sexual assault.

HARGROVE: Yes.

CHANG: What are the chances then, in your judgment, that these 51 are all by a single killer versus a few killers? Do you have any idea?

HARGROVE: It is extremely unlikely that these 51 women were killed by 51 separate men. That just did not happen. If you look at a large group of unsolved female murders within the same geography that have the same characteristics, most of the time, you're going to find serial activity. It could be one guy. It could be two or three guys. Serial murder is far more common than anyone really wants to admit.

CHANG: Well, that segues into something that Chicago Police Superintendent Eddie Johnson has been saying about the fact that there's no evidence of a serial killer so far. Let's listen to what he said.

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EDDIE JOHNSON: There's just simply nothing there right now that suggests that we have serial killers in the city of Chicago.

CHANG: What do you have to say to that?

HARGROVE: The superintendent is completely correct. There is a ton of evidence that has not been taken to the lab because the labs are backed up. It will take months or years to process all of that evidence unless a special grant can be found, possibly from the FBI.

CHANG: Well, evidence aside, are there additional reasons the police in Chicago might be reluctant to call this the work of a serial killer?

HARGROVE: Well, first of all, there's the well-known problem of linkage blindness. When someone is murdered, a detective is assigned to the case. When someone else is murdered, another detective is assigned. If there are commonalities between the two cases, those commonalities are not known unless the two detectives have a conversation over the watercooler.

Also, there's a certain amount of politics in serial murder, I'm sorry to say. The mayor wants a regular report. The superintendent wants a regular report. It can be a real headache. They have a lot on their hands. Is it fair to spotlight 51 particular cases? We think it is because history tells us that a serial killer will continue until he is stopped.

CHANG: Thomas Hargrove is the founder of the Murder Accountability Project. Thanks so much for coming in today.

HARGROVE: Thank you.

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