For more than two decades after a stranger raped a 21-year-old college student in her Bronx apartment, police could not solve the crime.

But a few years ago, as part of a new investigative technique, prosecutors say they found the DNA profile of one of the rapist’s distant relatives on a genealogical site. Through that profile, law enforcement was able to match the relative to a DNA sample from the crime scene. The NYPD’s forensic lab built out the family tree and used it to crack the long-unsolved crime.

A Bronx jury convicted Jancys Santiago of rape earlier this year, and a judge sentenced him on Friday to 25 years in prison. The Bronx district attorney’s office said he was the first person to be convicted by a New York jury in a sexual assault cold case using investigative genetic genealogy.

It has become increasingly common in recent years for investigators to use genetic genealogy sites like FamilyTreeDNA and GEDmatch to solve crimes and find missing people, from the Golden State Killer to an unidentified 9/11 victim.

Supporters of investigative genetic genealogy say it can be a powerful tool to zero in on possible suspects in languishing criminal cases, as well as to help to analyze unidentified human remains. But the technique has also sparked concerns about potential violations of privacy and civil liberties, prompting calls for more regulation.

Katie Kinsey, tech policy counsel at NYU’s Policing Project, said she hopes police and prosecutors will embrace guardrails as investigative genetic genealogy becomes more common in their work.

“That's going to enable law enforcement to use it in situations in which it's actually helpful and avoid the risks of situations where it can go wrong,” she said.

In Santiago’s case, investigative genetic genealogy helped to solve two sexual assaults that had confounded investigators for more than two decades.

In May 2000, 27-year-old Sarah Canavan Clark came home to her Midtown apartment and found Santiago wearing a mask and hiding in her closet, according to the Manhattan DA’s office. Canavan Clark spoke about the case at a press conference following the sentencing. Prosecutors said he threatened to kill Canavan Clark, forced her into the bathroom, tied her arms and feet with a wire hanger, and raped her.

The following December, Santiago entered 21-year-old Katy Vicchitto’s Bronx apartment while she was sleeping, covered her face, bound her with a wire hanger and raped her, prosecutors said. In court, Vicchitto said she felt “completely trapped” as both her home and her body were violently invaded. Speaking at a press conference after the sentencing, she said the trauma of the attack “changed nearly everything for me,” causing panic attacks, hypersensitivity and a fear of being alone.

Investigators ultimately solved both cases after the Bronx DA’s office received a $500,000 grant from the U.S. Department of Justice, which it used to solve cold cases with assistance from investigative genetic genealogy. Santiago, it turned out, lived in Vicchitto’s apartment building.

In the Manhattan case, Santiago waived his right to a jury, and a judge found him guilty of first-degree rape and first-degree burglary last year. The Manhattan judge sentenced him to 20 years in prison. On Friday, Bronx Justice Laurence Busching sentenced him to an additional 25 years — to run consecutively with the Manhattan sentence — because he said a “diligent and professional jury” had found him guilty. He said rape victims often carry the trauma of their attack for their entire lives. The judge also lauded Vicchitto for enduring the pain of having hairs pulled from her body after the attack in order to preserve the DNA evidence for a rape kit.

Santiago’s defense attorney, Michael Croce, said at the sentencing hearing that his client maintains his innocence and questioned the reliability of the science. He cited other scientific methods that have been used in the past to prosecute cases, only for them to be debunked later. Croce said Santiago plans to appeal.

But after the sentencing, Bronx DA Darcel Clark defended the method that secured his convictions.

“It’s reliable today, and it did what it was supposed to do today, which was to get justice in this case,” she said. “We don’t know what the future holds. But I know that 25 years ago it wasn’t possible, but it is today. And it’s reliable.”

‘They all deserve the truth’

When police are looking for a suspect in a crime, often they upload a DNA sample from the crime scene into the Combined DNA Index System, also known as CODIS. It’s a database of DNA profiles drawn largely from people who have been arrested or convicted of a crime. But CODIS doesn’t always turn up a match for a possible perpetrator, especially if the person has no prior involvement with the criminal justice system.

Investigative genetic genealogy provides another possible path forward. Investigators can upload the DNA sample to certain genealogy databases that allow law enforcement to view the profiles of users who grant them permission. Ancestry and 23andMe do not grant access to law enforcement, but some other sites, including GEDmatch and FamilyTreeDNA, do for users who opt in.

Investigative genetic genealogist Allison Peacock said once a DNA sample is uploaded into a genealogy database, investigators look for the matches' common ancestors.
They then use genealogical research to map out the family tree and find the point where the different ancestral lines converge, until they eventually home in on the person in question, she said.

“It’s a pretty exact science at this point,” she said.

In addition to people whose DNA doesn’t show up in a law enforcement database, investigative genetic genealogy can also be helpful to identify people whose DNA was collected a long time ago. Kinsey with the Policing Project said the technology is more effective at analyzing DNA that has degraded over time than traditional methods. That can make it particularly useful for cold cases.

“We need accountability in our society,” said Peacock, founder of the investigative genetic genealogy firm FHD Forensics. “ People that have been sexually assaulted or people that have been murdered or people that die unknown, they all deserve the truth. They all deserve justice, and they deserve accountability for the people that have harmed them.”

She said investigators should use all the tools at their disposal, as long as they are used “ethically and responsibly.” Peacock also said the findings of genetic genealogists are only leads, and that law enforcement must confirm them, such as by obtaining their own DNA sample through a warrant.

But Kinsey said the results of a genetic genealogy investigation can be “much stronger than just a lead.”

“ They can really point law enforcement to the person that they end up arresting,” she said. “They can shape the whole trajectory of a case.”

Policing research center recommends guardrails

The Policing Project issued a report in June that warned of several possible risks of investigative genetic genealogy, including revealing sensitive private information, like an affair. The report also flagged possible errors in the process with potentially high costs, such as contaminated DNA samples, flawed lab practices or mistakes with genealogical research. These issues could lead to invasions of privacy, wrongful arrests and useless diversions of police time and resources, according to the report.

Kinsey, one of the report’s authors, said investigative genetic genealogy can still be a valuable strategy, in spite of these risks. But she said there should be laws to minimize the risks. Only two states — Maryland and Utah — have comprehensive laws governing the use of investigative genetic genealogy, she said. New York lawmakers have repeatedly proposed a bill that would establish a policy for familial DNA searching in the state, but the proposal has never advanced out of the Senate committee.

The Policing Project’s report recommends several ways to regulate investigative genetic genealogy, including requiring that law enforcement tell defense attorneys when investigative genetic genealogy has been used in their client’s case, and that they confirm a DNA match using traditional methods before making arrests. It also recommends that genealogical data from public databases not be used by law enforcement without consent. And it calls for standards to ensure quality control in the investigative process, as well as sanctions for law enforcement who break the rules.

The research center suggests that the technology only be used to investigate violent crimes, missing people and unidentified human remains.

“That way we can  balance some of the trade-offs of the risks by making sure it's a more limited universe of cases that are even open to this methodology, and they're very serious cases where there's a pretty strong societal interest in trying to solve them,” Kinsey said.

Correction: This story has been updated to clarify the process for identifying common ancestors.