In April, the Golden State Killer, a former police officer responsible for a series of rapes and murders in the 1970s and '80s, was finally caught — thanks to a genealogy website.

Armed with the killer's DNA from various crime scenes, detectives used a website called GEDmatch to track down possible relatives who had similar genetics. This ultimately led them to a handful of suspects, one of whom fit the rest of the clues: Joseph James DeAngelo, a 72-year-old man living in a quiet neighborhood of Sacramento, California. Investigators were then able to collect a tiny bit of the man's DNA, taken from something he had thrown away, and then use this genetic material to confirm that he was the Golden State Killer.

Though catching a murderer is undoubtedly a good thing, the event sparked a debate on the ethics of using popular genealogy websites such as 23andMe and Ancestry.com to solve crimes. [Genetics by the Numbers: 10 Tantalizing Tales]

In a commentary published yesterday (May 28) in the journal Annals of Internal Medicine, three bioethicists from the National Institutes of Health (NIH) argued that law enforcement and genealogy websites should be transparent about how people's genetic information could be used in forensic investigations. The authors cautioned that this new method might be better used as an "investigative tool" rather than the primary way police convict people.

"This is a very powerful technology," said commentary co-author Benjamin Berkman, a faculty member at the NIH Department of Bioethics. "It can do things that I don't think we could imagine a few years ago."

And with this power, comes a new area that policy hasn't quite caught up with: "Police departments are starting to use it, and maybe [we need to] think a little bit about the kinds of rules and guidelines that they'll follow when they use it," Berkman told Live Science.

Do people know how their genetic data can be used?

"Many companies do not inform users that their information may be subject to forensic analysis," the authors wrote. "Others mention it in their terms of service, but whether users internalize (or even read) these documents is in considerable doubt."

In the biomedical world, evidence indicates that people are OK with their data being used for a wide range of scientific purposes, so long as they are asked permission first, the commentary said. But how people will respond to their information being used for forensic purposes remains a bit murky, especially since their data can be used to accuse others.

The Golden State Killer, for example, was caught because one of his distant relatives uploaded genetic data onto GEDmatch.

"Some people might be fine if their data indirectly leads to their cousin getting arrested for a crime that they committed," Berkman said. "But other people might not, and I think you can have a reasonable disagreement about that." So, "people should know that before they upload their data," he said.

Others may worry about the chance of erroneously convicting innocent relatives or people — though Berkman noted that he's less worried about this possibility. Police mostly use these sites to home in on suspects that they will then investigate more fully, he said. So your data probably won't convict your innocent relatives, he said, but further investigations might "inconvenience" them. [10 Amazing Things Scientists Just Did with CRISPR]

This is also a problem at crime scenes, the authors wrote. "Prosecutors and courts might overinterpret or misuse genetic identification as a source of evidence," the commentary said. "DNA evidence demonstrates only that an individual's genetic material was found at a given location, not that the person was present during, or indeed guilty of, the crime."

Are you abandoning your DNA when you upload it?

According to the authors, a genealogy search probably wouldn't count as a "search" under the Fourth Amendment (which protects against unlawful searches and seizures). But even if it did, there's something called the "abandonment doctrine," which holds that anything discarded (like DNA from cigarette butts at crime scenes) isn't protected under privacy laws. And technically, when people upload their DNA onto genealogy websites, they "abandon" it, the authors wrote.

"When you upload your data, it's sort of like you're throwing away a toothbrush," Berkman said. "Legally speaking, I'm not sure that you should have an expectation of privacy." However, he said, to his knowledge, there haven't been case studies exploring this idea, while there have been legal examinations of police searching through a suspect's trash. But whether or not it's good social policy to hold DNA uploaded onto genealogy websites to the same privacy laws as DNA abandoned in public spaces, is debatable, Berkman added.

Discrimination is also a concern, the authors wrote. "Worries remain that expansive use of forensic DNA analysis in any context may lead to discrimination, particularly if police departments aggressively target certain groups by using racial or ethnic markers when looking for individual suspects," the authors said.

According to Berkman, the use of genealogy websites for forensic purposes is becoming more and more common, but investigators are not publicizing it. Berkman and his co-authors concluded that it's important for both the investigators and the websites to be transparent that people's genetic data could be used or is being used for forensic purposes.

All of this is "not to say that we shouldn't use this technology, just that we should be more conscious of the trade-offs both as a society and as individual users," Berkman said.

Originally published on Live Science.