Tuesday, July 27, 2010
The development of DNA databases is helping investigators solve crime by looking for genetic near-matches -- results close enough to an already-stored DNA profile to suggest the crime was committed by a relative. Familial DNA database searches are based on the fundamental principle that DNA profiles of persons who are related are likely to contain similarities. Parents, siblings, and even more distant relatives such as aunts, uncles and cousins can be linked to crimes because a relative's DNA closely resembles DNA left behind at the crime scene.
In one of the earliest high-profile cases to use familial DNA, Dennis Rader, the BTK (Bind, Torture and Kill) killer, (right) was apprehended in 2005. Rader, who eluded authorities in the Wichita, Kansas, area for more than 30 years while killing 10 people, was ultimately tied to the crimes by his daughter's DNA sample. Law enforcement authorities had a suspect and were looking to tie him to the various crime scenes. Rader's daughter had given a Pap smear at a university clinic five years before. Investigators obtained a search warrant for that DNA specimen and determined that her DNA profile almost perfectly matched the DNA profile taken from several BTK crime scenes.
In a more recent case, Los Angeles police arrested 57-year-old Lonnie David Franklin Jr., a suspected serial killer, earlier this month by comparing DNA found at some of his crime scenes with the DNA of his son. The son was incarcerated in a California prison on a weapons charge. Franklin, known as the "Grim Sleeper" because of a 12-year hiatus between crimes, is accused of killing 11 people since 1985. The successful arrest was the end result of a controversial policy enacted in 2008, when the California Attorney General approved running a familial DNA search through the state's databases for major violent unsolved crimes.
The police found Franklin (left) by running a random comparison search throughout the databank that keeps DNA information for the California prison system. Franklin himself was not in that database, because despite two arrests, because he had spent his time in county jails rather than the state prison system. After zeroing in on Franklin's son and a near DNA match, investigators began following Franklin. They obtained his DNA from a discarded napkin and plate which he threw away after eating pizza.
The use of familial DNA searching has been a common practice in Europe, Australia and New Zealand for years. Since 2004, British authorities have conducted multiple investigations resulting in 18 matches and 13 convictions. The United States has been slower to embrace the practice because of technical, legal and ethical issues. To date, only Colorado and California have made wide use of the practice.
California allows near-match searches in major violent crimes where all other avenues have proven fruitless. Police are required to pursue all leads before a search is allowed. Colorado has allowed more widespread use of the practice to include nonviolent cases. Maryland, the only state to have addressed the issue statutorily, has banned the use of familial DNA searches altogether.
Last year, the F.B.I. decided not to reconfigure their CODIS DNA search software after hearing concerns of critics of familial searches. Thomas Callaghan, the former head of the F.B.I.'s national DNA database, worried that familial DNA searches may be legally vulnerable. He has said he fears that the courts may not look kindly upon using for one purpose samples originally collected for another. Civil libertarians cite constitutional guarantees against unwarranted searches and concerns about invading the privacy of persons whose only crime is having a relative in the database. They argue that it amounts to guilt by association. They also note that innocent family members could become unwitting informants against other relatives.
Denver District Attorney Mitchell R. Morrissey, an enthusiastic proponent of the use of familial DNA, defends the practice by arguing that it increases public safety. He believes that law enforcement has a responsibility to use available technology, in a constitutional and legal way, to protect communities. But Colorado ACLU Director Mark Silverstein questions the practice: "The use of so-called familial DNA matches dramatically expands the potential for invasion of privacy posed by law enforcement's ever-growing DNA databases."
No state has specifically allowed the use of familial searches, but 16 now permit the use of partial matching obtained through fortuitous circumstances, while prohibiting the use of deliberate familial searching. In addressing the controversy, Peter Marone, director of the Virginia Department of Forensic Science, says: "This is much more than a scientific issue. There are other policy issues involved."
It is clear that there must be safeguards to ensure that the technique is not abused, and to minimize the potential for erroneous matches merely because a DNA profile is similar. However, the use of familial DNA searching could revolutionize criminal investigations. It is hard to ignore a technology that has the potential to apprehend violent predators before they have the chance to prey on additional victims. How does one tell a victim or surviving family member that we had the technology to prevent the crime but we couldn't use it?
Try telling that to the family member of what could have been a future victim of BTK or the Grim Sleeper.
Statements made in this post are my own and are not intended to reflect the views, opinion or position of the Michigan Attorney General or the Michigan Department of Attorney General.Tweet