- Whenever I see data,
I tend to think in terms of patterns.
The real world is following rather simple
mathematical formula.
And it's that way with murder.
Most people don't realize that we're far
less likely to solve a murder today
than we were 50 years ago.
My name is Thomas Hargrove,
and I am the founder and chairman
of the Murder Accountability Project.
I'm not a police officer.
Quite frankly I am just a nerd.
I really know very little about serial killers.
I do know what they look like in data.
For 37 years I was a newspaper reporter,
and it was just the best job there is in the universe.
Increasingly I became known as the numbers guy
in the newsroom.
We wanted to study why murders go unsolved
and why a growing number of murders go unsolved.
And the first time I saw the Supplementary Homicide Report
by the FBI, my first thought was I wonder
if we could teach a computer to spot
serial killers in these data.
And the answer is yes.
Years before I had learned of a phenomenon
called linkage blindness.
The only way the murders are linked
to a common offender is if the two investigators
get together by the water cooler
and talk about their cases and discover commonalities.
We contacted the FBI and got every year's worth
of reporting back to 1980.
I opened it up and looked at row after row of individual murders.
It had the victim's age,
race, sex, how the victim was killed.
We turned that into a nine-digit number,
essentially a Dewey Decimal System of death.
During the months that I was working on the algorithm,
I had over my desk a picture of Green River
killer, Gary Ridgway.
He killed 48 women in Seattle in the '80s and '90s.
He was looking at me for months and months
while I was trying to make an algorithm work.
The only way we would know that an algorithm
was successful is if it was identifying
known serial killers.
What worked was a technique called cluster analysis.
And we told the computer to cluster the data.
Seattle came up clear as day something awful had happened,
and the algorithm was producing dozens
and dozens of other clusters that looked
just as bad as Seattle that were not known.
Like Gary, Indiana, there were actually 15
unsolved strangulations of women in the area,
including 13 in Gary itself.
I contacted the Gary Police Department
and gave them my usual spiel.
I'm Tom Hargrove, we have a method to
identify serial killers.
There have been too many unsolved strangulations.
What do you know about it?
Absolute radio silence.
They would not talk about the possibility
there was a serial killer active.
In 2014, just next door to Gary,
Hammond police were summoned to a Motel 6.
Dead woman in the bathtub.
They make an arrest.
Very quickly Darren Vann started confessing
that he had been at this for decades
going back to the '90s.
In all, seven women died after we had tried
repeatedly for months to get them to consider
the possibility that they had a serial killer.
This was, without question, the most frustrating
experience in my professional life.
I have absolutely no doubt that many of
the unsolved strangulation murders of women
in Gary, Indiana are Mr. Vann's handiwork.
We have more than 220,000 unsolved murders
in the United States.
We've gathered records on more than
23,000 murders that were never reported
to the Justice Department.
And we are continuing.
We can see where unreported murders are
and we go to police departments and say
you must start reporting data.
I'm gonna do what it takes to start solving murder.
That's our dream and that's why we try
to take homicide data as available as possible.
There is an algorithm that can identify
serial killings and does.
What's more serious than murder?
What's more serious than serial murder?
What's better than having a computer
be able to identify things that human beings are missing?
Catching killers saves lives,
and so whatever we can do,
we'd be doing the Lord's work.