The Justice Served Act, passed by the US House of Representatives on Tuesday evening by a 377–1 vote, would mandate that 5% to 7% of the money used by the Department of Justice for testing rape kits go toward prosecutors investigating cold cases. If passed by the Senate and signed into law, that would mean that at least $6 million of the program’s $120 million budget would go to state and local prosecutors' offices, rather than crime labs.

“This bill will allow us to prosecute criminals identified through DNA testing, and ensure they are never given the opportunity to commit such crimes again," the bill's lead sponsor, Rep. John Carter of Texas, told BuzzFeed News in a statement.

When investigating crimes with DNA, police typically use databases run by the FBI or individual states to compare crime scene samples with DNA profiles collected from people arrested or convicted of crimes. In recent years, investigators in some states have not only looked for exact matches but also have used state databases to search for partial matches that might come from a suspect’s close relatives.

This has solved a number of cold cases, including the Grim Sleeper, a serial killer responsible for at least 10 murders in Los Angeles. Lonnie David Franklin Jr. was arrested for the crimes in 2010 after his son was convicted on a felony weapons charge and his DNA profile showed up in the FBI database.

The Golden State Killer case was solved by a much more laborious method. There were no partial matches in the FBI’s database, but investigators were able to find more distant relatives by uploading a DNA profile from a 1980 crime scene into a public database called GEDMatch, used by genealogy enthusiasts. The profile contained hundreds of thousands of genetic markers, rather than the 20 or fewer used for conventional DNA forensics.

Investigators then used census data and other public records to construct family trees to link these distant relatives of the killer to potential suspects. It took five people four months before they identified Joseph James DeAngelo as their prime suspect.

Former FBI scientist Bruce Budowle of the University of North Texas Center for Human Identification told BuzzFeed News that it’s unclear how often such an extensive effort could be justified. While no cost is too high from victims’ points of view, prosecutors and detectives need to husband their resources to conduct all kinds of investigations.

“They don’t have the budget nor the people” to widely investigate cases using genealogical methods, Budowle said.

“It’s not the DNA typing — that’s trivial,” he said. It’s the thousands of hours needed to construct family trees linking distant relatives to potential suspects.

Cold case advocates are thrilled. "Anything that will help eliminate the backlog for DNA results needs serious consideration,” Sheryl McCollum of the Cold Case Investigative Research Institute told BuzzFeed News by email. “There is zero excuse for a case of recovered DNA to take a year to get results back!”

Even though the bill diverts some money from efforts to test backlogged rape kits, sexual assault advocates are in favor of it. There has been progress in reducing the backlog in testing DNA from arrests and convictions nationwide; the backlog was 500,000 samples in 2009, down to around 64,000 samples in 2014.

"We support this bill and every effort the federal government is putting forward to address the backlog of untested kits," Melissa Schwartz of the Joyful Heart Foundation, an advocacy group for sexual assault survivors, told BuzzFeed News.