Familial DNA Testing

by Emily Zvejnieks

Familial DNA testing, an innovative yet highly controversial technique, is being used in several states. This blog post will provide an explanation of what familial DNA testing entails and briefly discuss its Fourth Amendment implications.

In standard DNA testing where there is an unknown sample, that unknown sample may be compared against samples in the Combined DNA Information System (CODIS), an index maintained by the FBI. The index is made up of samples of convicted offenders and individuals who have been arrested or charged with certain crimes but not yet convicted. Traditionally, the unknown sample is compared against known samples in the database, looking for an exact match.

In situations where an unknown sample exists but a search of an existing DNA database returns no exact matches, it is possible to conduct a search to identify potential relatives of the alleged perpetrator. This process is called familial DNA testing. The actual process is a low-stringency search, which produces inexact matches. The search is based on the idea that those closely related to each other share more genetic data than those not closely related.

There are two pending U.S. cases currently in the spotlight where defendants were identified as a result of familial DNA testing in California and Wisconsin. Lonnie Franklin, Jr., also known as the alleged “Grim Sleeper” serial killer, is charged with several counts of murder for crimes that occurred in Los Angeles in the 1980s and 2000s. In that case, authorities obtained the perpetrator’s DNA from various crime scenes. After running the DNA through the offender database with no exact matches and no other suspects, the sample was submitted for familial searching, and the search rendered a result of a potential first-degree family member. Detectives then determined that Lonnie Franklin, Jr., the father of the person whose DNA sample was in the database, lived in close proximity to most of the crime scenes.  An undercover officer then followed Franklin to a local pizza joint and, after Franklin was finished with his plate, collected his plate, pizza, and utensils. After testing DNA obtained from his leftovers, authorities matched the unknown sample to Franklin. Franklin has since been charged with ten counts of murder and one count of attempted murder, and his cases are pending.

Wisconsin recently used familial DNA testing for the first time. The case involves pending sexual assault charges against Michael L. Dixon.  A series of similar rapes that occurred between 2008 and 2012 in Milwaukee remained unsolved until a familial DNA search was performed using the perpetrator samples from the crime scenes. Using familial DNA testing, there were two close matches. Upon further investigation, it was determined that one of those matches did not have any male first-degree relatives, so that possible match was eliminated. The other close match did have a brother: Michael L. Dixon, who had been found not guilty of a 2012 rape with similar facts to the unsolved rapes. Wisconsin authorities had Dixon’s DNA sample from his arrest on the 2012 charges, but his DNA was never added to CODIS since he was not convicted. The perpetrator’s DNA from the unsolved rapes and Dixon’s DNA were an exact match. Dixon now awaits trial for first and second degree sexual assaults.

The Innocence Project opposed the use of familial DNA testing in a February 2013 position paper.  Interestingly, California implements many of the safeguards the Innocence Project suggests regarding admissibility of evidence procured through familial DNA testing. Michael Chamberlain, Deputy Attorney General of the California Department of Justice, wrote an article published by the American Bar Association in 2012 that lays out familial DNA testing use and practice.  California uses its own software called the “ratiometer.” After coming up with 150-200 possible close matches, the ratiometer runs a Y-STR test, which analyzes the Y chromosome only to determine whether there is a matching Y-STR profile. If Y-STR profiles match, that indicates there is a paternal relationship. Because the California process uses the Y-STR test, familial DNA testing cannot be used for females and also does not identify half-brothers who share the same mother.

Fourth Amendment implications of familial DNA testing are mind-boggling.  On one hand, we know that a defendant does not have a Fourth Amendment claim when his or her privacy interests were not violated.  Many of the samples entered into CODIS belong to convicted felons who, according to our justice system, gave up some privacy interests by way of their actions.  Familial DNA testing is a search of those samples.

On the other hand, the reason that there is no exact match in the CODIS database and familial DNA testing is being done is because the suspected perpetrator is not a convicted felon and thus his or her privacy rights have not been compromised.  Each person shares DNA with his or her parents, siblings, and children.  If one of them has given a sample due to being a convicted felon, or even gives a sample voluntarily, then their relatives’ DNA can be analyzed as well.

Arguably, familial DNA searching falls under the “technology not in general public use,” as discussed in Kyllo v. United States. In Kyllo, SCOTUS held that a thermal imaging device used to determine excess amounts of heat inside a private residence was a search as the technology employed was not in general public use.  Kyllo, 533. U.S. 27 (2001). Similarly, DNA searching is a technology not in general public use, and it could be argued that familial DNA testing is a search requiring a warrant – otherwise it would be a way for the government to get around Fourth Amendment protections of a person whose family member’s DNA is in a database.

Another concern with the use of familial searching is that it will create suspects out of innocent people simply because they are related to someone whose DNA is in a database and their relative’s DNA is similar to DNA found at a crime scene. Because of the racial makeup of the existing DNA databases, people of color will be disproportionately impacted. Innocent citizens will become subjects of police investigation, and will bear the privacy, emotional, economic, and liberty costs associated with being investigated for a crime.

As familial DNA searching becomes more widely used in the United States, it will be interesting to see what North Carolina as well as the Supreme Court of the United States decide on its use and admissibility. To date, the only known case where this technique has been used in North Carolina is the Darryl Hunt case. Certainly any jurisdiction choosing to perform familial DNA testing should implement stringent requirements for its use. For more information, this website offers a four-part webinar series on familial DNA testing.

Other Sources:

42 U.S.C. 14132.

Kyllo v. U.S., 533 U.S. 27 (2001).

Bruce Vielmetti, First use of Familial DNA test leads to charges in serial sex assaults, Milw. J. & Sent., July 11, 2014, http://www.jsonline.com/news/crime/new-dna-technique-leads-to-serial-raper-charges-say-b99309491z1-266827171.html.

Chamberlain, Michael, Familial DNA Searching: A Proponent’s Perspective, Crim. Just., Volume 27, Number 1, Spring 2012.

FBI, Familial Searching, http://www.fbi.gov/about-us/lab/biometric-analysis/codis/familial-searching.

Global Justice Information Sharing Initiative, An Introduction to Familial DNA Searching for State, Local, and Tribal Justice Agencies: Issues for Consideration, https://it.ojp.gov/gist/111/An-Introduction-to-Familial-DNA-Searching-for-State–Local–and-Tribal-Justice-Agencies.

Kim, J., Danny Mammo, Marni B. Siegel, and Sara H. Katsanis, Policy Implications for Familial Searching, Investig. Genet., http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3253037/.. November, 1, 2011.

Symposium, Family Ties:  The Use of DNA Offender Databases to Catch Offenders’ Kin, 34 J.L. Med. & Ethics 248 (2006).

Weiss, Lindsey. All in the Family: A Fourth Amendment Analysis of Familial Searching.  The Selected Works of Lindsey Weiss.  Available at:  http://works.bepress.com/lindsey_weiss/2.

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