'Grim Sleeper' Case Brings Familial DNA To Fore

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Last week, Los Angeles police announced they'd arrested a suspect in a 25-year serial murder investigation of a killer known as The Grim Sleeper. The big break came when police linked an unidentified DNA sample from the crime scene to DNA from the suspect's son. It's the first big forensic case involving what's called familial DNA. Robert Siegel talks to David Lazer, editor of the book DNA and the Criminal Justice System, about what many are calling a game-changing use of genetic fingerprinting.


Late last week, the Los Angeles police made an arrest in the case of The Grim Sleeper, a killer who had eluded them for 25 years and at least 10 murders.

Mayor ANTONIO VILLARAIGOSA (Los Angeles, California): Thanks to the recent use of DNA evidence and, even more importantly, two decades of exhaustive detective work, we have our suspect.

SIEGEL: That's Los Angeles Mayor Antonio Villaraigosa.

Detectives had recovered samples of the killer's DNA from crime scenes but they never got a match in law enforcement databases. So they tried familial DNA testing. They looked for genetic profiles in the database that were close enough matches that they might come from relatives of the suspect. Ultimately that test led them to the son of their suspect, then to the suspect himself, who was arrested and charged with the crimes.

Familial DNA is extremely rare. Some people have raised concerns of privacy and civil liberties.

Joining us to talk about is David Lazer, associate professor of political science and computer science at Northeastern University, and editor of the book "DNA and the Criminal Justice System." He's an advocate of this technique.

And welcome to the program, David Lazer.

Professor DAVID LAZER (Political Science/Computer Science, Northeastern University): Hello. Thank you for having me.

SIEGEL: And first, how rare is familial DNA testing?

Prof. LAZER: Well, it has not been widely used in the United States. Primarily it has been used to some extent in Colorado and in California. And this is the, really, the biggest success story. There was a notable case in North Carolina, where actually they got not only a familial match, but then they - that also resulted in the exoneration of someone who had been in jail for some time, Darryl Hunt.

SIEGEL: Ten unsolved murders in the L.A. case, with a pile of DNA evidence from multiple crime scenes - this sounds like the ideal application for this kind of technique, when you have no doubt as to the DNA of the person you're looking for. Can you imagine it being used, though, in a variety of other situations?

Prof. LAZER: The facts in this case where you have matching evidence from multiple crime scenes then matching a suspect, looks like a pretty compelling case. However, there are going to be more difficult cases where, let's say, you have a cigarette butt at a crime scene. May or may not be from the perpetrator of the crime but, you know, thats a more general problem with any investigation is that sometimes some of the facts, some of the clues mislead you to the wrong person.

SIEGEL: What do you think of the argument that criminal databases reflect the population of people whove been charged with crimes; they are disproportionately black and Hispanic; a disproportionate number of blacks and Hispanics with ner-do-well cousins or absentee fathers, whove committed crimes, could find themselves under police surveillance if this technique were used widely?

Prof. LAZER: Well, it's definitely troubling that indirectly brings in, you know, potentially tens of millions of people into the database, and they're going to reflect the demographics of the people who have their samples in the database. And that system is already tilting heavily in the direction of African-Americans, Hispanics. That is certainly, I think, something that is troubling about the use of familial searching.

SIEGEL: By the way, when we speak of all the databases that law enforcement might check to see if somebody is in there, I think the military database is still off limits to criminal investigators, but how many people are we talking about? How many Americans have genetic profiles that might be accessed and might be part of a search?

Prof. LAZER: The size of the offender database in the United States is a bit over eight million people. And that currently is the only database that is systematically searched.

SIEGEL: You know, on TV shows, someone says let's check the DNA and five minutes later someone from the crime lab walks in with the answer. What are we talking about nowadays in terms of delays to actually get an answer to a question about a DNA match?

(Soundbite of laughter)

Prof. LAZER: Well, if you want to get someone from a crime lab irritated, you make some implications that their life is just like what you see on "CSI." It takes far more than five minutes. It takes months.

Obviously, if you have a serial murder case, that goes to the front of the line. And in this particular case, they did the analysis very quickly. Not as quickly as you see on "CSI," but very quickly.

SIEGEL: Professor Lazer, thanks a lot for talking with us.

Prof. LAZER: Okay. Thank you so much, Robert.

SIEGEL: That's David Lazer of Northeaster University. He's the editor of the book "DNA and the Criminal Justice System."

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