WIRED reports on a disturbing new trend: the practice of using DNA samples from databases like the one used by Ancestry.com to investigate DNA evidence from cold cases.

The article hinges on the experience of a man named Michael Usry. Last year, Usry was investigated for a 1998 crime because DNA evidence from the scene was a partial match with DNA his father had donated to a Mormon genealogy project that later sold their samples to Ancestry.com’s DNA library, a database that’s accessible by law enforcement.

Usry, whose story was first reported in The New Orleans Advocate, was finally cleared after a nerve-racking 33-day wait—the DNA extracted from his cheek cells didn’t match that of Dodge’s killer, whom detectives still seek. But the fact that he fell under suspicion in the first place is the latest sign that it’s time to set ground rules for familial DNA searching, before misuse of the imperfect technology starts ruining lives.

There are a few states that have taken the first pre-emptive steps towards resolving this issue, namely California, Colorado, Virginia, and Texas, but there’s still not any kind of definitive statute about how much of this information law enforcement can utilize.

Worst of all is that there’s no concrete evidence proving that agencies using these publicly searchable resources will definitively lead to the closing of more cases.

“Anyone who knows the science understands that there’s a high rate of false positives,” says Erin Murphy, a New York University law professor and the author of Inside the Cell: The Dark Side of Forensic DNA. The searches, after all, look for DNA profiles that are similar to the perpetrator’s but by no means identical, a scattershot approach that yields many fruitless leads, and for limited benefit. In the United Kingdom, a 2014 study found that just 17 percent of familial DNA searches “resulted in the identification of a relative of the true offender.”

As libraries of genetic information builds in the years to come, it’s important for governments at the state and federal level create stricter measures to avoid false convictions, and perhaps more importantly, to keep innocent people from feeling compelled to needlessly turn over their own genetic fingerprints.

For more on this fascinating topic, head over the full story at WIRED.