November 01, 2019 Feature

DNA Evidence in Sexual Assault Cases: Past Trends and Future Potential

Cassidy Kesler Pinegar

Genetic genealogy—a combination of DNA testing and traditional genealogical research—emerged as a cutting-edge approach in law enforcement investigations after authorities in California used it last year to identify a suspect in the long-unsolved Golden State Killer case. On April 24, 2018, law enforcement arrested Joseph James DeAngelo, a 73-year-old former police officer believed to be the assailant in a series of murders, rapes, and assaults in California during the 1970s and 1980s. In a last-ditch effort to solve crimes that had been cold for decades, law enforcement entered crime-scene DNA into a public genealogy and DNA database called GEDmatch. The DNA of one of DeAngelo’s relatives was in GEDmatch, leading investigators through familial research to identify DeAngelo as a possible suspect. Law enforcement conducted additional investigation, including surreptitiously obtaining a sample of DeAngelo’s discarded DNA to compare directly to the crime-scene DNA, and ultimately arrested DeAngelo based on the results. DeAngelo has since been charged with 13 serial murders and is suspected to have committed more than 50 rapes. (Paige St. John, Death Penalty Sought for Golden State Killer Suspect, L.A. Times (Apr. 10, 2019).)

Following the success of the Golden State Killer investigation, many jurisdictions began using genetic genealogy to solve crimes, particularly cold cases. For instance, within a few months of the Golden State Killer arrest, authorities in Takoma, Washington, used genetic genealogy to solve the 1986 rape and murder of a 12-year-old girl. (Lindsay Bever, A 12-Year-Old’s Murder Went Unsolved for Decades. Police Just Used a Napkin to Find a Suspect., Wash. Post (June 26, 2018).) Authorities in Lancaster County, Pennsylvania, used genetic genealogy to solve the 1992 rape and murder of a 25-year-old teacher. (Kyle Swenson, Undercover Cops Grabbed a DJ’s Chewing Gum. It Helped Crack a Teacher’s 1992 Murder, Police Say., Wash. Post (June 26, 2018).) And authorities in Seattle, Washington, used genetic genealogy to solve the 1967 rape and murder of a 20-year-old woman. (Gene Johnson, DNA, Family Tree Help Solve 52-Year-Old Seattle Murder Case, AP News (May 7, 2019), One source estimates that more than 60 criminal cases were solved using genetic genealogy in the year after DeAngelo’s arrest. (Id.)

Genetic genealogy is made possible by the ever-increasing number of people who have purchased consumer genetic tests from companies such as 23andMe and AncestryDNA. Consumer genetic tests can provide information about family origins, health risks, and other traits. Estimates vary, but one source reported that more than 15 million people had sent DNA samples to these companies as of October 2018. (Heather Murphy, Most White Americans’ DNA Can Be Identified Through Genealogy Databases, N.Y. Times (Oct. 11, 2018).) People who want to find relatives across testing companies used can upload their DNA results to an open-source website like GEDmatch or FamilyTreeDNA. (Tina Hesman Saey, Crime Solvers Embraced Genetic Genealogy, Sci. News (Dec. 17, 2018, 8:32 am),

Genetic genealogy has the potential to be particularly effective in solving sexual assault cases thanks to three trends in using DNA evidence that have emerged over the past two decades: (1) criminal charges based on a DNA profile when the suspect is otherwise unidentified; (2) legislative changes to statutes of limitations to account for DNA evidence; and (3) efforts to reduce or eliminate the nationwide backlog of untested sexual assault cases. A “John Doe” indictment issued last year in a sexual assault cold case in Washington, DC, is a useful starting point for examining these past trends.

United States of America v. John Doe

On May 1, 2018, a grand jury in Washington, DC, returned an indictment against “John Doe,” identified by a unique DNA profile only, with 17 charges including aggravated sexual assault, burglary, kidnapping, robbery, and assault with a dangerous weapon. (Indictment, United States v. John Doe, with the following DNA profile: TPOX: 8, 11, etc., Crim. No 2018 CF1 006590 (Super. Ct. D.C. May 1, 2018), The indictment concerns two separate sets of crimes with different victims, both hotel housekeepers, who were attacked on May 11 and May 23, 2003. The indictment was returned shortly before the end of the 15-year statute of limitations period on the sex offenses and thus preserved the ability of law enforcement to pursue charges against the assailant if and when he is identified. (D.C. Code § 23-113(a)(2) (2018); Peter Hermann & Michael Brice-Saddler, The Hotel Rapist’s Name Is Still a Mystery, but “John Doe” Has Been Indicted, Based on His DNA Profile, Wash. Post (June 19, 2018).)

Law enforcement publicized the John Doe indictment a month after its return, asking for tips from the public and information to help identify the unknown suspect. (Press Release, U.S. Attorney’s Office D.C. (June 19, 2018), This was the first time the US Attorney’s Office for the District of Columbia had sought a John Doe indictment based on a DNA profile. Law enforcement revealed that the suspect is believed to have committed between six and nine violent sexual assaults at hotels in Maryland, Virginia, and Washington, DC, between 1998 and 2006, including the charged offenses. The suspect was definitively linked to six of the attacks by DNA evidence and was linked to three additional attacks by other evidence. Law enforcement released a composite sketch of the suspect from 2003 based on witness reports, as well as an age-progressed composite sketch that was created using the DNA left behind by the suspect. At present, no arrest has been made.

Past Trends in DNA Evidence in Sexual Assault Cases: John Doe DNA Profile Indictments

Like the 2018 case in DC, prosecutors began using John Doe DNA profile indictments in the late 1990s and early 2000s as a means of bringing criminal charges in sexual assault cases— and thereby tolling or complying with the statute of limitations—when a suspect’s DNA profile is known, but the suspect is not otherwise identified. One of the first John Doe DNA indictments was obtained in 1999 in Wisconsin by then–Milwaukee County Assistant District Attorney Norman Gahn in a serial-rape case shortly before the six-year statute of limitations would have expired. (Meagan Flynn, The Culprit’s Name Remains Unknown. But He Licked a Stamp, and Now His DNA Stands Indicted, Wash. Post (Oct. 17, 2018).) According to The Washington Post, Gahn estimated that his use of John Doe warrants led to the arrest of a dozen perpetrators in the early 2000s. (Id.) Prosecutors in jurisdictions across the country from California to New York adopted this approach around the same time as Wisconsin.

John Doe DNA profile charging documents have been challenged in court on various grounds. Defendants have claimed that using a DNA profile to identify the subject of a charging document is insufficiently particular under the Constitution, state constitutions, and relevant statutes. In addition, defendants have argued that DNA profile charging documents do not effectively toll the statute of limitations and allowing them to do so would undermine the purpose of such statutes. There are further concerns that, depending on the length of time between the bringing of charges and trial, the use of John Doe DNA charging documents may violate a defendant’s right to a fair and speedy trial under the Sixth Amendment to the Constitution and equivalent state constitutional provisions. Defendants have also asserted that DNA profile charging documents violate due process by failing to provide adequate notice of the underlying charge and by creating prejudicial pre-indictment or pre-charging delay.

The first state high court to rule on the validity of DNA profile charging documents was the Wisconsin Court of Appeals in 2003. In State v. Dabney, the original complaint and warrant in a sexual assault case identified only a DNA profile and were obtained just days before the statute of limitations would have expired. (264 Wis. 2d 843, 849 (Wis. Ct. App. 2003).) The complaint and warrant were later amended to add Dabney’s name when the DNA profile matched in a database with Dabney’s profile. (Id.) Dabney contended that the court lacked personal jurisdiction over him because the complaint and warrant did not satisfy the “reasonable certainty” identification requirements of Wisconsin law. (Id. at 850–51.) The Wisconsin appellate court rejected this claim and explained that a suspect whose name is unknown may be identified by “the best description available.” (Id. at 853.) The court found that “for purposes of identifying a ‘particular person’ as the defendant, a DNA profile is arguably the most discrete, exclusive means of personal identification possible.” (Id. at 854.) The court noted that including any known physical appearance characteristics in the warrant and complaint would have been helpful from a notice perspective, but the failure to include such characteristics in addition to the DNA profile did not invalidate the charging documents. (Id.)

Dabney also argued that the DNA profile–based complaint and warrant should be deemed inadequate to satisfy the statute of limitations or the purposes of the statute would be undermined by the indefinite tolling of the criminal action. (Id. at 855.) The court rejected Dabney’s position, finding that the statutory period was effectively and properly tolled by the DNA profile–based complaint and warrant. (Id.) The court noted that the statute of limitations is not a fundamental right but a statutorily created right intended to protect a defendant against charges of remote misconduct. (Id. at 856.) The court found that the purpose of the statute of limitations was not violated because the charges were brought using a sufficiently particular charging document within the six-year limitations period. (Id.)

In addition, Dabney asserted that his due process rights were violated in two ways because the DNA profile complaint and warrant (1) did not give him sufficient notice of the charge and (2) resulted in prejudicial pre-indictment delay. (Id. at 858.) The court rejected both of these arguments as well. The court held that a defendant is not entitled to notice of the underlying charge until the warrant is executed and the warrant at issue was not executed until Dabney’s name had been substituted for the DNA profile, satisfying the notice requirement. (Id.) The court further held that Dabney did not establish any actual prejudice resulting from pre-indictment delay and did not show that the delay in filing the complaint resulted from an improper prosecutorial motive or purpose intended to give the state a tactical advantage. (Id. at 859–60.) Accordingly, all of Dabney’s challenges to the John Doe DNA profile charging documents were rejected and his convictions for kidnapping and sexual assault while armed were affirmed.

State courts in Ohio, New York, California, Massachusetts, Tennessee, and Utah have relied on similar reasoning to reject challenges based on particularity or notice requirements and to uphold the use of John Doe DNA indictments and warrants in sexual assault cases. (State v. Danley, 138 Ohio Misc. 2d 1 (Comm. Pl. 2006); State v. Martinez, 52 A.D.3d 68 (N.Y. App. Div. 2008); People v. Robinson, 47 Cal. 4th 1104, 1134 (2010); Commonwealth v. Dixon, 458 Mass. 446 (Mass. 2010); State v. Burdick, 395 S.W.3d 120 (Tenn. 2012); State v. Younge, 321 P.3d 1127 (Utah 2013).) In State v. Danley, the Court of Common Pleas of Ohio also considered a constitutional speedy trial challenge to John Doe DNA profile charging documents under the framework set forth in Barker v. Wingo, 407 U.S. 514 (1972), and Doggett v. United States, 505 U.S. 647 (1992), and found no constitutional speedy trial violation in that case. (Danley, 138 Ohio Misc. 2d at 7.) In addition, the Kansas Supreme Court has recognized, “in the abstract,” that a warrant setting forth a unique DNA profile can satisfy constitutional and statutory particularity requirements. (State v. Belt, 285 Kan. 949, 960 (Kan. 2008) (finding that warrants at issue in consolidated cases before the court contained insufficient DNA information for purposes of identification because they contained information about only two DNA loci).) More recently, state courts in Minnesota and Arizona have upheld the use of John Doe DNA profile indictments and warrants in non–sexual assault cases, specifically in burglary cases. (State v. Carlson, 845 N.W.2d 827 (Minn. Ct. App. 2014); State v. Neese, 236 Ariz. 84 (Ariz. Ct. App. 2016).) Many jurisdictions, including the District of Columbia, have not yet ruled on these issues.

Legislative Changes to Statutes of Limitations

From the outset, John Doe DNA profile charging documents were both championed and criticized as a way around statutes of limitations in sexual assault cases. (Frank B. Ulmer, Using DNA Profiles to Obtain “John Doe” Arrest Warrants and Indictments, 58 Wash. & Lee L. Rev. 1585, 1611–20 (2002).) Criminal statutes of limitations serve valuable societal purposes—such as enabling prosecutions to be based on fresh evidence, promoting repose, and encouraging the prompt investigation of crimes—which arguably are undermined by the use of John Doe DNA profile indictments. (Id.) Given this tension it is unsurprising that the advent of John Doe DNA profile indictments was accompanied by a reevaluation of statutes of limitations for sex offenses and other cases in which DNA evidence is recovered. (Id. at 1621–23.)

In 2003, just four years after John Doe profile indictments were first used in Wisconsin, the state legislature passed a law that tolled the six-year statute of limitations in cases where DNA evidence was recovered and a DNA profile was isolated but no match could be made to identify the perpetrator. (State v. Dabney, 264 Wis. 2d 843, 857 (Wis. Ct. App. 2003).) The court in Dabney noted that this statutory change “demonstrates the legislature’s recognition that DNA profiles do sufficiently identify sexual-assault offenders and that the competing interest in sexual assault prosecutions weigh in favor of allowing such prosecutions to commence after six years when the state has obtained the offender’s DNA profile but has been unable to match it to a known DNA profile within that period.” (Id.) The new law in Wisconsin gave prosecutors 12 months to bring charges after a DNA match is made, striking a new balance between the statute of limitations and DNA evidence. (Id.)

Between 2000 and 2005, 20 states changed their statutes of limitations to account for DNA evidence and 10 additional states considered such changes. (Corey E. Delany, Seeking John Doe: The Provision and Propriety of DNA-Based Warrants in the Wake of Wisconsin v. Dabney, 33 Hofstra L. Rev. 1091, 1093 (2005).) By 2013, 25 states had statutory DNA exceptions to the limitations period, New York recognized an exception rooted in common law, and Arizona tolled the limitations period for serious offenses when the identity of the offender is unknown. (Brittany Ericksen & Ilse Knecht, Statutes of Limitations for Sexual Assault: A State-by-State Comparison, Nat’l Ctr. Victims Crime (Aug. 21, 2013)) Although the specifics differ by jurisdiction, a DNA exception to the statute of limitations will generally toll the limitations period if DNA evidence is recovered and set a period of time within which charges must be brought if and when a DNA match is made. Because DNA-based exceptions to statutes of limitations allow prosecutors to bring criminal charges after a DNA match is made, there is no reason to indict a John Doe DNA profile in jurisdictions with such an exception.

Similarly, there is no reason to indict a John Doe DNA profile when there is no statute of limitations applicable to a particular crime. Statutes of limitations for sex offenses vary from state to state depending on the seriousness of the offense and the age of the victim. As of 2018, 10 states had eliminated the limitations period for filing charges in all or nearly all felony sexual assaults, regardless of the age of the victim. (Ruth Padaer, Should Statutes of Limitations for Rape Be Abolished?, N.Y. Times Mag. (June 19, 2018).) Many states are considering or making changes to the limitations period for sex offenses. For instance, in April 2019 Washington State eliminated the statute of limitations for sex crimes involving minors and extended the limitations period for rape cases involving adult victims from 10 to 20 years. In June 2019, the New York State legislature passed a bill removing the statute of limitations for the most serious sex offenses and extending the limitations period for other sex offenses.

When the John Doe indictment was obtained in DC in May 2018, there was no DNA exception to the statute of limitations and the limitations period for first-degree sexual abuse was 15 years. (D.C. Code § 23-113(a)(2) (2018).) In the months after the John Doe indictment, following the trend that began two decades ago, the DC Council passed a law removing time limits for prosecution of first-degree sexual abuse and many other felony sex offenses. (Sexual Abuse Statute of Limitations Amendment Act of 2018, D.C. Act 22-593.) The new law, which went into effect on May 23, 2019, also requires police to keep evidence related to certain sex crimes for 65 years from the date of first reporting and expressly eliminates the practice of using fictitious name indictments. (Id.)

Legislative changes to statutes of limitations based on DNA evidence reflect a judgment that the potential value to society of resolving a case using DNA outweighs the value of the general reasons for the adoption of criminal statutes of limitations in the first place. These values remain in tension, however, and the tension is heightened in cases where DNA evidence is collected but not tested in a timely manner. When DNA evidence is collected but untested for whatever reason—lack of financial or technical resources, law enforcement negligence or deliberate exclusion, absence of legislative directives or political will—there is a stronger argument that tolling the limitations period until a DNA match is found compromises the defendant’s ability to investigate and build a defense, giving rise to claims of spoliation of evidence and prejudicial delay. Where statutes of limitations have been extended or removed, defendants may seek relief under the Fifth Amendment Due Process clause and state constitutional equivalents, under which an indictment is subject to dismissal if the defendant can show that prosecutorial delay caused substantial prejudice to a defendant’s right to a fair trial and resulted from an improper purpose to gain a tactical advantage. (United States v. Marion, 404 U.S. 307 (1971).) Courts and legislatures will have to continue to try to balance these difficult issues as jurisdictions increasingly address the backlog of untested DNA evidence, particularly in sexual assault cases.

Testing the Backlog of Sexual Assault Kits

In the early 2000s, around the same time that prosecutors began using John Doe DNA profile indictments and legislatures began considering changes to statutes of limitations based on DNA evidence, jurisdictions across the country began grappling with the fact that thousands upon thousands of sexual assault kits were collected but never submitted for DNA testing. Sexual assault kits contain the evidence collection tools used by medical professionals during medical-forensic examinations of victims of sexual assault. During a sexual assault examination, which can take between four and six hours, the doctor or nurse will thoroughly examine the victim and collect evidence, including taking photographs and swabbing the victim’s body for biological material. Each kit contains forensic evidence, including DNA, that could potentially identify the perpetrator who committed the alleged assault. When a sexual assault kit is tested and one or more DNA profiles are sufficiently identified, the profile may be compared to a DNA sample obtained from a suspect. The profile may also be uploaded into the FBI’s nationwide databank, the Combined DNA Index System (CODIS). A “hit” occurs in CODIS when the DNA profile matches the profile of an individual whose DNA is in CODIS, or when it matches the profile of a suspect in another crime who is not yet identified. In this way, uploading DNA profiles into CODIS allows law enforcement to connect different cases across jurisdictions and to identify serial offenders.

Although it is logical to assume that the swabs in a sexual assault kit would always be promptly submitted to a DNA laboratory for testing, historically that has not been the case. In the absence of laws or guidelines about when and which sexual assault kits to test, the decision is generally made on a case-by-case basis by detectives or prosecutors. This decision is informed by many factors, including case-specific facts and circumstances, such as whether the perpetrator is already known to the victim, whether the victim is cooperative with law enforcement, the investigator’s assumptions and biases, and the cost of DNA testing. On a macro level, scholars have identified several reasons for the backlog of untested sexual assault kits, including collection of sexual assault kits before DNA forensic analysis was widely available, prioritization of testing a limited number of kits given the expense of testing, victim-blaming behaviors and beliefs, lack of written policies and protocols for submitting kits for testing, budget cuts that reduced the number of sexual assault investigators and crime lab personnel, inefficient DNA testing methods and/or equipment, high turnover in police leadership, strained relationships between police and prosecutors, viewing of sexual assault kits as a prosecutorial rather than investigative tool, delays in obtaining testing results, lack of community-based advocacy services, outdated record keeping, and no centralized storage location for sexual assault kits. (Rachel Lovell et al., Describing the Process and Quantifying the Outcomes of the Cuyahoga County Sexual Assault Kit Initiative, 57 J. Crim. Just. 106 (July–Aug. 2018).)

Since the prevalence of untested sexual assault kits came into focus two decades ago, many jurisdictions have made efforts to address the backlog of untested kits, resulting in the identification of numerous offenders and the resolution of previously unsolved cases, both sex offenses and other crimes. The experience of the Manhattan District Attorney’s Office demonstrates the far-reaching impact of testing backlogged sexual assault kits. Between 2000 and 2003, New York City eliminated its backlog of more than 17,000 untested sexual assault kits. (Press Release, N.Y. Cty. Dist. Att’y, D.A. Vance Delivers Remarks at Press Conference Announcing Results of Rape Kit Testing Investment (Mar. 13, 2019), Testing backlogged kits led the District Attorney’s Office to obtain indictments in dozens of cold cases based on DNA matches and to help solve crimes across the country. (Id.) Motivated by the results of testing backlogged kits in its own jurisdiction, in 2013, the Manhattan District Attorney’s Office invested $38 million (from money seized in prosecutions against major banks) in a three-year program that provided grants for the testing of backlogged sexual assault kits in 32 different jurisdictions across 20 states. (Id.) In March 2019, the Manhattan District Attorney reported the results of the grant program: More than 55,000 kits were tested and more than 18,000 newly developed DNA profiles were entered into CODIS. (Id.) The testing had already led to 186 new arrests and 64 new convictions, including 47 new sexual assault convictions. (Id.)

The federal government and jurisdictions across the country, including Los Angeles, Detroit, Cleveland, and many others, joined New York City in making efforts to eliminate the widespread backlog of untested sexual assault kits. In 2015, the Bureau of Justice Assistance launched the National Sexual Assault Kit Initiative (SAKI) with the purpose of creating a coordinated community response to address the backlog of untested kits and promote the just resolution of sexual assault cases. By the spring of 2019, SAKI had identified 200,000 untested sexual assault kits in 54 jurisdictions across 35 states and submitted more than 47,000 kits for testing. (Over 47,000 Kits Tested Through BJA’s Sexual Assault Kit Initiative Since 2015, Bureau Just. Assistance, U.S. Dep’t Just. (Apr. 26, 2019), Between September 2015 and December 2018, SAKI funded efforts resulted in 14,913 DNA profiles entered into CODIS, 6,137 investigations, 961 cases charged, 104 convictions, and 444 cases resolved by plea agreement. (Performance Metrics & Research, Sexual Assault Kit Initiative,

Submitting previously untested sexual assault kits for DNA testing has reinvigorated the investigation of numerous sexual assault cases across the country and in many cases has led to the identification and prosecution of offenders, including suspects originally charged in John Doe DNA profile indictments. In Memphis, Tennessee, a woman was sexually assaulted by a stranger in 2000. The sexual assault kit was not tested until 2012; the suspect’s DNA profile was indicted three years later in 2015. The suspect was eventually identified after a burglary charge in Oklahoma led to a DNA match. He was convicted on the rape charges in October 2018. (“John Doe” Indictment Leads to Conviction in 18-Year-Old Rape Case, WMC Action News 5 (Oct. 15, 2019, 9:51 PM),

As jurisdictions have addressed the backlog of untested sexual assault kits, law enforcement has been required to determine which cases—among the many cases with now-tested evidence—to investigate and potentially prosecute. Typically, the most serious cases receive priority, including crimes committed by serial offenders. Arizona and Ohio are two examples of the many jurisdictions that have identified serial rapists from testing backlogged kits. In 2014 law enforcement in Pima County, Arizona, began prioritizing the testing of sexual assault kits. In 2015 the Tucson Police Department received a $1 million grant from the Manhattan District Attorney’s Office to support its testing effort. Within the first month of testing funded by the grant, police focused investigative efforts on one of the DNA profiles that came up in more than one kit, ultimately leading to the conviction of a man for raping seven women over a 12-year period. (Alexandra Svokos, Serial Rapist Nathan Loebe Convicted in Pima County, Arizona, After Testing of Rape Kit Backlog, ABC News (Mar. 2, 2019, 7:56 AM), When authorities in Cleveland, Ohio, began testing their backlog of untested kits, they identified approximately 207 suspected serial rapists believed to be responsible for almost 600 attacks. (Press Release, Cuyahoga Cnty. Office of Prosecutor, Serial Rapists Responsible for at Least 600 Attacks Linked to Untested Evidence, Authorities Believe (Mar. 21, 2015), Among these cases was a former probation officer who was linked by DNA to 22 different rapes. (Id.)

Legislatures have acted to complement, encourage, and, in some circumstances, compel efforts by law enforcement to test backlogged sexual assault kits and prevent the development of future backlogs. In 2018 the Ohio legislature passed a bill to support a tracking system for sexual assault kits that would allow victims to keep track of the state and location of evidence from their cases. (Jeremy Pelzer, Ohio Lawmakers Pass Bills to Create Rape Kit Tracking System, Cleveland Plain Dealer (Dec. 15, 2018).) According to End the Backlog, a program of the nonprofit organization Joyful Heart Foundation, Ohio is one of 46 states that have taken steps toward statewide reform relating to the backlog of untested sexual assault kits; only four states (Alabama, Mississippi, North Dakota, and Rhode Island) have taken no action toward statewide reform. (Where the Backlog Exists and What’s Happening to End It, End the Backlog, Along these lines, the city council in Washington, DC, passed an ordinance in 2014 requiring that the police submit sexual assault kits for testing within seven days of a victim filing a report and the crime lab complete testing within 90 days of receipt. (D.C. Code § 4-561.02.) In 2018, the mayor of the District of Columbia announced that the city had eliminated its backlog of untested sexual assault kits. (Megan Cloherty, Formerly Disgraced DC Crime Lab Eliminates Rape Kit Backlog, WTOP (Jan. 2, 2018, 4:03 PM),

Resolving the backlog of untested sexual assault kits is an ongoing process with significant work left to do. While many jurisdictions have made notable strides in the past two decades through the actions of law enforcement and legislatures, there are still an unidentified number of sexual assault kits to be tested, cases to be investigated, and offenders to be prosecuted.

Future: Potential of Genetic Genealogy

The three trends briefly discussed in this article have all had the same general effect: DNA evidence is being used to investigate, prosecute, and resolve sexual assault cases more effectively than in the past. These trends have also set the stage for the continued future application of genetic genealogy to sexual assault cases. Genetic genealogy has the potential to help law enforcement identify suspects charged in John Doe indictments, avoid the future use of John Doe indictments, and investigate offenders in cases where DNA evidence was previously untested. Genetic genealogy has already brought numerous cold cases back to life, as evidenced by the investigative successes of the past year. In addition, it has the potential to prevent new cases from going cold.

The use of genetic genealogy to solve crimes is not without controversy, however. Concerns about individual and genetic privacy—weighed against law enforcement needs and victims’ rights—have been at the forefront of discussions about genetic genealogy. These concerns include the fact that individuals who took consumer genetic tests and uploaded them to public databases did so for their own private purposes, usually to find relatives, and not for the purpose of helping law enforcement identify which, if any, of their relatives committed unsolved crimes. Whether, what type, and in what manner law enforcement should be allowed to access public DNA databases has been much debated over the past 18 months. In late May 2019, GEDmatch (the database used in the Golden State Killer case) announced that it would change its terms of service so that users will need to opt in to allow law enforcement to see their data. (Seth Augenstein, GEDmatch Changes Are “Blow” to Law Enforcement—and Forensic Genealogy, Forensic Mag. (May 20, 2019, 9:21 AM)) Previously, users had to opt out to avoid law enforcement access. (Id.) GEDmatch did not point to a specific case as a reason for the change, but experts believe it was prompted by the use of genetic genealogy to find a suspect in the violent assault of a senior citizen in Utah, a serious crime but not one contemplated by the company’s use policy then in place. (Id.) Many believe that changing the default setting from opt-in to opt-out will limit law enforcement’s ability to use GEDmatch to solve crimes and identify bodies. (Id.) However, FamilyTreeDNA, another genealogy and DNA data base, still has an automatic opt-in setting that allows law enforcement access when investigating cases of homicide, sexual abuse, or abduction, unless the user specifically opts out. (Id.)

Additional concerns stem from the fact that the DNA information that is uploaded to public genealogy and DNA databases is more extensive than the DNA information generally available to law enforcement through CODIS. CODIS contains enough unique DNA information to identify an individual without revealing additional information about the individual’s appearance, ancestry, or health traits. In contrast, consumer genetic tests and public genealogy and DNA databases collect highly personal DNA information about ancestry and health by design. Given this difference, there is an argument that uploading a suspect’s DNA information to a public database violates the suspect’s right to privacy and the right to privacy of the suspect’s biological relatives. (Christine Guest, DNA and Law Enforcement: How the Use of Open Source DNA Databases Violates Privacy Rights, 68 Am. Univ. L. Rev. 1015 (2019).)

Law enforcement, the broader criminal justice system, the genetic genealogy community, and the public are still in the beginning stages of identifying the issues and concerns raised by genetic genealogy and working out how genetic genealogy can and should be used in future criminal investigations, including sexual assault cases.


If the suspect charged in the 2018 John Doe DNA profile indictment in DC committed his crimes today instead of in 2003, the sexual assault kits would be submitted for testing within a week of each victim making a report, and the DNA testing would be completed within 90 days. There would be no need for a John Doe indictment, even if a DNA match is slow in coming, because DC no longer has a statute of limitations for first-degree sexual assault. Moreover, the chances of finding a DNA match are better because the nationwide effort to test backlogged kits has led to an increased number of DNA profiles in CODIS, profiles of both identified offenders and suspects linked to other crimes but otherwise unknown. In addition, if approved in the jurisdiction and permitted by available DNA genealogy databases, law enforcement could use genetic genealogy to identify and investigate potential suspects.

The way society in general and law enforcement in particular respond to sexual assault is not perfect. Certainly, there is room for improvement in many areas, both within and beyond the scope of this article. Even so, the progress made in the past two decades—illustrated by the three trends in the use of DNA evidence discussed above—has resulted in more effective investigation and prosecution of sexual assault crimes and has set the stage for the use of genetic genealogy to resolve even more cases.


Cassidy Kesler Pinegar is an attorney in Overland Park, Kansas. She served as an assistant United States Attorney in Washington, DC, from 2006 until 2018, where she specialized in prosecuting sex offense and child exploitation crimes.