Controversial DNA Forensic Technique Catches California Serial Killer

Robert Enneser by Robert Ennesser

On July 7, 2010, Lonnie David Franklin, Jr., was arrested and accused of murdering eleven people between 1985 and 2007.  Franklin had been dubbed the "Grim Sleeper" because he is believed to have taken a 14 year hiatus from killing between 1988 and 2002.  What led to his arrest after 25 years of eluding police? A controversial technique known as a "familial DNA search," in which DNA evidence from Franklin’s victims or crime scenes was closely matched to DNA obtained from his son.  Franklin’s son was convicted of a felony, and DNA collection is a normal procedure after a felony conviction.  Despite the success of the police in catching a serial killer, there is debate as to whether it is fair to use family members’ DNA to track down criminals.

On the national level, DNA information is stored by the FBI in the Combined DNA Index System (CODIS), which contains more than 8 million genetic profiles.  It has assisted in more than 116,000 investigations, including nearly 11,000 in Illinois.  Each CODIS profile contains information from 13 genetic markers composed of short tandem repeats (STRs) – repeated patterns of DNA scattered throughout the genome. Initially, CODIS included only violent felons but subsequently expanded to include all felons and later all felon arrestees.   Individual states have their own databases with differing inclusion requirements.  Some states do not expunge DNA profiles of arrestees later found innocent, other that do often require long, complicated procedures.  The FBI does not use familial DNA searches, but states are free to use the searches if they choose.  As a result, in California and Colorado, DNA of people never convicted of a crime and not under individual suspicion can be compared against DNA found at a crime scene. 

Mitch Morrissey, the District Attorney in Denver, believes familial DNA searches are a valuable tool for law enforcement.  The DNA of a close family member will closely match the suspect’s DNA, but will not be identical.  Morrissey likens a close, non-identical match – a "partial DNA hit" – to having an eyewitness who only remembers half of a license plate.  Familial DNA searches have the potential to increase the efficiency of law enforcement and generate leads that can point investigators in the right direction.  Alternatively, if familial DNA evidence leads to someone who is innocent, than the DNA or other evidence can quickly clear that person and the police can move on to the next lead.  

Familial DNA searches seem like a powerful tool for law enforcement, but there are concerns about the practice including potential privacy violations as well as racial disparities in the DNA databank. 
Hank Greely, Professor of Law and Genetics at Stanford University, says "[t]he idea that the sins of the fathers would be visited on the children is a troubling one in our society" (referencing Exodus 34:7 in the Bible).  The Fourth Amendment of the United States Constitution protects people against unreasonable searches and seizures without probable cause.  If the crime scene partially matches the DNA of someone in CODIS, how is that probable cause to search a relative?  Various relatives – parents, siblings, and children – would be potential targets.  

Greely is also troubled by the racial implications due to databanks disproportionately composed of minorities.  This is primarily due to the facts that African Americans represent 13% of the U.S. population but 40% of prison inmates.  Innocent family members of criminals identified through DNA databanks could be targeted, including disproportionate numbers of African Americans.  Greely estimates that 17% of African American citizens could be identified and investigated via familial DNA searches, as opposed to 4% of Caucasians.  Fear of a civil rights backlash was one reason the FBI decided not to conduct familial DNA searches on a national level. 

While the FBI does not conduct familial searches, states are free to do so.  As of November 2009, as study showed 19 states permitted partial match reporting or familial searches while 17 states had prohibitions on the practices (13 states declined to participate and Illinois had "unclear" policies).  Even when states utilize the technology, a United Kingdom survey revealed the success rate of familial DNA searches is only 10%.  While a 10% success rate may not be enough to justify widespread use of the practice, Professor Jeffrey Rosen of George Washington University suggests that when a DNA databank search is coupled with a Y-chromosome analysis or other evidence, it may ease some privacy concerns.  The use of DNA databank information in conjunction with additional evidence is the approach currently used in California.  Under the California model, familial DNA searching is limited to high priority cases – where other investigative methods have failed – and requires Y-chromosome analysis and non-forensic evidence whenever possible.  The method used to catch the Grim Sleeper demonstrates this approach in action:  (1) a close DNA match was made between DNA found from victims or at the crime scene and the convicted DNA donor (Franklin’s son), which showed a close familial relationship;  (2) the Y chromosome profiles of the two samples matched, which showed a strong paternal relationship;  (3) additional information collected, including geographic location, demonstrated Franklin was a viable suspect;  and (4) a "Familial Search Committee" reviewed all of the data and provided the information to police asserting that there was a “reasonable probability” that the Grim Sleeper was a family member of the convicted DNA donor. 

Today, the Grim Sleeper is behind bars to await trial – his right under the Sixth Amendment.  His capture is the success story proponents of familial DNA searches have sought to encourage use of the practice, but the technique is still young and protocols governing its use need to be explored and implemented.  According to medical geneticist Frederick Bieber, the California model appears to represent a satisfactory compromise between reasonable privacy and maximally-effective law enforcement.  Police can take advantage of powerful forensic DNA technology, while the required approval from an oversight committee creates a "reasonably probable" standard for law enforcement. 

A DNA profile is one piece of evidence.  Like other types of evidence, it can shift an investigation in the right direction.  A DNA profile, like any piece of evidence, can also lead to questioning of innocent individuals and unfortunately sometimes harassment.  If additional facts and circumstances incriminate an individual to a reasonable probability, however, then it is fair for that person to be investigated after an extensive review with the blessing from a Familial Search Committee.  New technology utilizing the power and information contained in the human genome should be adopted, but only when it is used in a just and fair manner crafted by state legislatures and overseen by the courts.