The man who raped a 22-year-old woman at knifepoint at an Acton train station in 2013 left his DNA during the assault, but his identity remained a mystery for years. Investigators found no matches in law enforcement criminal offender databases, and the case went cold.
Then, in February, authorities announced a major breakthrough: Investigative genetic genealogy — and an open bottle of Fireball cinnamon whiskey — led to the arrest of Christopher Aldrich of Lunenburg.
The 28-year-old Aldrich is charged with aggravated rape, in what Middlesex District Attorney Marian Ryan said is the first prosecution by her office involving investigative genetic genealogy — an innovative technique using commercial genealogy databases that first captured national attention in 2018 when it led to the arrest of the so-called Golden State Killer. Now, police are turning to it more and more to zero in on murderers and rapists and to give names to human remains that were unidentified.
The technique can be expensive and time-consuming and authorities say they will require more resources to expand its use. Meanwhile, privacy advocates have called for more oversight and regulation of law enforcement’s use of databases used by people to trace their roots.
But legal and criminal justice analysts predict investigative genetic genealogy — the technique of identifying criminals and victims by searching genealogy databases for people who share their DNA — will ultimately become a mainstream law enforcement tool.
“It’s changing the way we investigate and solve crimes,” Ryan said in an interview. “It is the wave of the future.”
Massachusetts State Police Colonel John E. Mawn Jr. has asked scientists from the Forensic Services Division to “examine the steps, resources, and policy considerations necessary” to perform this type of testing in-house, according to an agency spokesman.
In Aldrich’s case, prosecutors say, authorities paid Virginia-based Parabon NanoLabs to upload the rape suspect’s DNA profile to a commercial genealogy website, which showed people who shared various amounts of his DNA — indicating whether they were near or distant relatives. Those people had voluntarily submitted their DNA for testing while tracing their ancestry and agreed to share the results with law enforcement. Then, investigators compiled family trees and scrubbed public records and social media, ultimately leading to Aldrich as a potential suspect.
Last fall, with Aldrich now identified as a suspect, Acton police obtained his DNA from a bottle of Fireball seized from his car after he struck a pole and was charged with drunken driving, according to Ryan.
Authorities announced in February that Aldrich’s DNA profile allegedly matched that of the rape suspect. He pleaded not guilty in Concord District Court and is being held while awaiting trial. His lawyer did not respond to requests for comment.
Ryan said her office is currently using genetic genealogy in an effort to solve about a dozen rapes and murders. She said the cost varies, depending on how many DNA tests are required, and it’s generally “multiple thousands of dollars.”
Over the last five years, hundreds of cold cases throughout the country have been solved with genetic genealogy, according to authorities.
In early March, authorities announced they had identified a young woman found shot to death in Granby in 1978. In October, a half century after a woman known only as the “Lady of the Dunes” was brutally murdered in Provincetown, officials announced that she was identified as a Tennessee native.
The technique has also led to breakthroughs in active cases. Several media outlets reported that police used genetic genealogy to identify Bryan Kohberger as a suspect in the murders of four University of Idaho students in November.
Civil rights advocates have been raising privacy concerns about investigative genetic genealogy and called for more regulation over the companies’ databases and oversight of police, labs, and genealogists involved in the process. In 2021, Maryland and Montana became the first states to pass laws restricting law enforcement’s use of genetic genealogy, requiring prior approval from a court and limiting it to certain types of cases.
Only two genealogy companies, GEDmatch and FamilyTreeDNA, allow law enforcement access to their databases, with restrictions to protect customers’ privacy. Those restrictions were put in place when privacy rights concerns were raised after the Golden State Killer case. Law enforcement officials are required to identify themselves to administrators of the databases in advance, and are shown information only from people who have agreed to share it, according to the companies’ websites.
Erin Murphy, a professor at New York University School of Law and author of “Inside the Cell: The Dark Side of Forensic D.N.A.,” said there’s a lack of accountability and transparency by law enforcement about genetic genealogy investigations, raising concerns about whether the privacy of people who are not suspects is being invaded.
“The problem right now is it’s not regulated so we can’t assume it’s subject to rules that we’ve all agreed on,” said Murphy, noting that when people share their DNA in genealogy websites, they are identifying past, present — and future — relatives.
“When people ask, ‘What’s wrong with capturing murderers?’” Murphy said, “I would ask, ‘At what cost?’”
Kristen Setera, a spokeswoman for the FBI’s Boston office, called investigative genealogy “an incredibly important technique” that the FBI is using to generate new leads to help police resolve cold cases. She stressed that when the FBI submits a DNA profile to the genealogy databases, it only gets what any other customer would get: a list of people who are related and the percentage of DNA they share.
Authorities say that restrictions by genealogy companies, as well as Justice Department guidelines issued in 2019, adequately balance privacy rights with the need to solve violent crimes. Those guidelines limit the use of genetic genealogy to homicides, sexual assaults, and violent crimes or attempted violent crimes that pose a threat to public safety or national security.
Barbara Rae-Venter, a genealogist at the vanguard of genetic genealogy technology who helped identify the Golden State Killer, said it would be more difficult to solve the case now because of the restrictions and she doesn’t understand why the capture of a serial killer and rapist triggered a backlash over privacy.
“I had someone tell me that I was violating [the killer’s] genetic privacy. That guy abandoned his DNA all over the state of California. What sort of privacy did he have?” said Rae Venter, who recently authored a book, “I Know Who You Are,” chronicling some of the early cases she helped solve.
Stephen Kramer, a former FBI attorney who led the team that captured the Golden State Killer and who cofounded the FBI’s forensic genetic genealogy team in 2019, said people do not generally have a reasonable expectation of privacy when they voluntarily share their information with the public on social media, including public genealogy websites.
Kramer said genetic genealogy has the potential to solve thousands of cases every year, if police departments create a budget for it and provide training on how to use it.
In 2021, Kramer cofounded Indago, a company that is developing artificial intelligence software to automate the process of building family trees and dramatically reduce the time it takes to identify a suspect.
Colleen Fitzpatrick, founder of Identifinders International, has worked on several hundred cases using genetic genealogy and described the technique as “a real game changer in human identification.”
But, she said, the technology is costly, and not every police department has bought into it. She said costs may start at around $6,500 to identify human remains and $9,000 to identify violent offenders. The price varies, according to experts, depending on how many DNA samples are analyzed, how long it takes a lab to build a DNA profile, and whether genealogy research is done by private companies or law enforcement officials.
One lab in Texas, Othram, runs a crowdfunding website that raises money for genetic genealogy investigations that help police identify victims. Earlier this month, the lab analyzed the DNA of the woman found shot to death in Granby in 1978 and helped identify her as Patricia Ann Tucker, 28, who vanished after dropping her 5-year-old son off with a babysitter.
“Thank you for never giving up on her,” the woman’s son, Matthew Dale, said in a statement after her identity was announced. “At least I have some answers now after 44 years.”
Correction: The original version of this story misspelled the name of the Texas laboratory Othram. The Globe regrets the error.