My Sister, My Mother: Family DNA Nabs Suspects It may usher in an age of genetic surveillance, but a law enforcement initiative to raid medical records for family DNA can be critical to solving crimes, according to Frederick Bieber, a medical geneticist and Harvard professor.
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My Sister, My Mother: Family DNA Nabs Suspects

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My Sister, My Mother: Family DNA Nabs Suspects


My Sister, My Mother: Family DNA Nabs Suspects

My Sister, My Mother: Family DNA Nabs Suspects

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

It may usher in an age of genetic surveillance, but a law enforcement initiative to raid medical records for family DNA can be critical to solving crimes, according to Frederick Bieber, a medical geneticist and Harvard professor.

Dennis Rader, who admitted to being the so-called "BTK killer," is escorted to prison in El Dorado, Kansas. Rader pleaded guilty after DNA evidence from his daughter linked him to 10 killings dating back to 1974. Larry W. Smith/AFP/Getty Images hide caption

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Larry W. Smith/AFP/Getty Images


In 2005, Dennis Rader of Wichita, Kansas, was arrested for the murders of ten people, murders which went unsolved for three decades. Rader was the BTK Killer. He was caught, in part, because a few years prior, his daughter had had a pap smear, and the DNA from that specimen was matched to crime scene DNA left by her father.

The daughter's DNA was obtained with a court order, but the entire issue of familial DNA is something that law enforcement is now having to deal with, as detailed in a story that we ripped from the headlines of the Washington Post this week.

One of the experts interviewed for that article is Frederick Bieber, a medical geneticist and associate professor of pathology at Harvard Medical School. Hello, Professor Bieber.

Dr. FREDERICK BIEBER (Medical Genetics and Pathology, Harvard Medical School): Good morning, Mike. How are you?

PESCA: I'm well. I think that when people hear about DNA being used to catch the BTK Killer, and where that DNA came from, they might think it's something, like, sci-fi. But is it a technique very common in law enforcement today?

Dr. BIEBER: It's gaining a lot of interest around the world. In the UK, Mike, these methods of indirect identification of someone's DNA through a relative have happened a couple dozen times now with success, and most of the U.S. states are thinking about these methods, deciding what policy issues they would consider important before they would even begin implementing it. There has been some controversy about the practice.

PESCA: But different states have different rules, and why is that? Why is there not one standardized method of treating familial DNA?

Dr. BIEBER: Well, remember, Mike, the laws that allowed law enforcement to take DNA from a convicted offender occurred throughout the 1990s. So each of the 50 states has different laws, and the federal government has its own set of laws that deal with federal offenses and military offenses.

So, each of the states initially took DNA from offenders after the most serious of felony crimes, murder and sexual assault. Over the years, most of the states now, over 40, will take DNA after a conviction for any felony, and 11 states, Mike, will now collect DNA upon arrest.

So, the laws have been different, and none of them really address the issue of familial searching. That is searching a database, not just looking for a perfect match to crime-scene evidence, but a close match, which could indicate a close relative, most commonly, a brother.

PESCA: DNA is in medical databases because - in the case of Dennis Rader's daughter, she was a student at Kansas State, so that's a state school, and she used state funding to get her pap smear. Is that why the state has access to some medical DNA and not others?

Dr. BIEBER: Well, yes. We have to separate the medical collections of DNA for diagnostic purposes from the DNA databases used after crimes have been committed. Most of the time, the DNA collected in a medical setting is private, and personal, and no one else would have access to it.

There are some exceptions, however, to the federal HIPAA legislation that allow police and law enforcement under certain extreme circumstances like the Wichita, Kansas, rape cases, to take DNA by court order without someone's knowledge or consent, and that's what happened in the Rader matter.

They suspected him, they didn't want to alert him to the fact that he was a suspect, but they wanted to be sure that the DNA from the crime scenes matched him, so they did what we call a reverse paternity test. They got DNA from his daughter without her knowledge.

And they asked the rhetorical question, could the semen evidence from these crimes belong to the biological father of the owner of the pap-smear DNA? And when the answer to that question was yes, they then got a court arrest warrant for Rader, and that's how they broke that case.

PESCA: In the - is the question just yes, because in this Washington Post article that we ripped from the headlines, there are percentages often quoted, like, there is a 90-percent chance that a relative of the person would have committed the crime? Is that - does it usually go by percents, or simple yes/no, answers?

Dr. BIEBER: Well, no, it goes by percent, because a lot of us could share DNA in common, but have no biological relationship. Just because some of the genes that exist at these markers that are tested are common enough that you, and I, and Rachel on your show could all share some DNA in common even though we're not related.

But blood relatives who have common ancestors, like father, daughter, have at least half their DNA in common because we get half of her DNA from dad, and half from mom. So, in that case it - we compute what's called the likelihood ratio, or a probability of paternity, and that's what's done in this sort of unique case.

PESCA: The tension with this entire field is best expressed by a couple quotes in the article that we're ripping off. One is, the science advisor to the ACLU says that, if this technique is practiced routinely, we would be subjecting hundreds of thousands of innocent people who happen to be relatives of individuals in the FBI database to lifelong genetic surveillance.

On the other hand, a New York State district attorney says of the foot-dragging and not allowing cops to have access to this, quote, "It's insanity. It's disgraceful. If I've got something of scientific value that I can't share because of imaginary privacy concerns, it's crazy. That's how we solve crimes." Well, what advice would you give to a governor who calls you in and says, you know, how do I decide about how to use this DNA?

Dr. BIEBER: What I do, Mike, is set up a commissioner board, and actually, New York State has one, the Commission on Forensic Science, that meets in Albany three or four times a year. I would set up a commission and make sure that these methods are used in the most extreme cases when all leads have failed.

I think Tania Simoncelli's comment is a bit off the mark, as she says that, if this was used routinely, we'd have this and that problem. No one has suggested that the method be used routinely. It's sort of a last resort, as it was in the Rader case, to look for the comparison of DNA to a relative. But in the UK where they have a panel, an advisory panel like I would recommend, they've used it sparingly - maybe 20, 30 times, but they've had great success when they've had to use it.

PESCA: Since the U.S. is more diffuse than the UK, for instance, you know, one central agency pretty much deals with all the crime there, do we have any idea how often it's been used in the U.S., familial DNA?

Dr. BERBER: We have no idea how often it's been used in the U.S. Most of the states, if they've used it, aren't talking much about it. One important case where it had success was in the Darryl Hunt investigation in North Carolina.

Darryl had been convicted, it turns out, erroneously of the rape and murder of a woman named Deborah Sykes over 20 years ago. He - the DNA testing, when it was done years later after the technology became available, excluded him. The court still kept him in prison, because they said while maybe he didn't...

PESCA: Right, right.

Dr. BERBER: Rape her, but he might have murdered her, and it was only when they used...

PESCA: And he was exonerated. We have to leave it there. Frederick Bieber of Harvard. Thanks very much.

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