The San Antonio Police Department is launching a new forensic genetic genealogy program aimed at solving some of the city’s most stubborn cold cases — backed by just over $1 million in federal funding.
The new funding will support the use of a specialized form of DNA analysis to identify suspects in homicide and sexual assault cases, when traditional investigative leads have run dry.
Police officials say the goal is simple: bringing resolution to cases that have sat unsolved for years and in some cases, decades.
“These are cases where traditional investigative leads have been exhausted, but the need for justice has never gone away, and never will until the cases are closed,” SAPD Police Chief William McManus said on Wednesday. “With this funding, we can bring answers to the families who have been waiting too long, far too long for justice.”
While investigators already rely on the national Combined DNA Index System, or CODIS — a law enforcement database that matches crime scene DNA to profiles collected from convicted offenders and arrestees — forensic genetic genealogy works differently.
Instead of requiring a direct match, the process allows investigators to search for partial matches in public genealogy databases, such as GEDmatch, where individuals voluntarily opt in their DNA to learn about their ancestry.
Those databases are often built from people who have used at-home DNA testing kits — like AncestryDNA or 23andMe — and then uploaded their genetic data to third-party platforms that allow broader comparisons. In some cases, users can also opt in to allow law enforcement searches.
Analysts use those partial matches to identify possible relatives of a suspect — sometimes distant ones — and begin building out family trees. From there, detectives rely on traditional investigative work, including public records, timelines and location data, to narrow down potential suspects before confirming a match with standard DNA testing.
“It’s not going to be, oh, that’s him,” said Captain Russ Van Geffen, who leads the homicide department. “There still has to be traditional work done to corroborate that information.”
Since 2018, the approach has been used to help solve more than 1,000 cases nationwide, through GEDmatch’s Genetic Witness Program.
Over the past five years, the city has recorded 366 unsolved homicides and 49 unsolved sexual assaults that could be eligible for forensic genetic genealogy.
The total number of cases stretches far beyond that.
“Just in the five years, there’s 366, take that times 10 going even farther back,” Van Geffen said. “It’s a large number.”
Still, not every case will qualify.
Investigators must have viable suspect DNA to begin the process, and the quality of that evidence can vary. In some cases, samples may be too limited or too complex, such as mixtures involving multiple individuals, for labs to produce reliable results.
Van Geffen said cases will be prioritized based on the strength of the available genetic evidence.
“The prioritization will be based on the evidence that we have,” he said. “That will make it a priority versus others. In a sexual assault case with a SANE exam, we have suspect DNA — those can be worked fairly quickly.”
A Sexual Assault Nurse Examiner (SANE) exam is a medical forensic examination performed by trained nurses for sexual assault survivors.
The new funding will allow SAPD to expand its use of the technology, something the department has previously done in a limited capacity with assistance from agencies like the Texas Rangers and the Texas Attorney General’s Office.
The $1.03 million allocation was secured by U.S. Rep. Joaquin Castro through a federal community project funding request — part of a program that allows members of Congress to direct funding toward local initiatives.
“Today, we declare that we are determined to solve every single one of these unsolved cases,” Castro said. “If you murdered somebody in San Antonio, whether it was last year or 40 years ago, we are determined to find you.”
While the funding will launch the program, Van Geffen said the volume of cases — and the cost of testing, which can range from $20,000 to $30,000 per case — means it is only a starting point.
“It’ll never be enough, just because we want to solve them all, “ he said. “This is a great start, and it’ll do a countless number of cases.”
