Another example tonight of DNA being used to solve a murder mystery.

Two years ago, California investigators were still searching for the person known as the Golden State Killer who raped and murdered 13 women. Police had been trying to find a suspect for more than 40-years.

As part of that effort 6 investigating attorneys asked the state of Nevada to take DNA samples of all its prison inmates to see if any of them matched the killer-a search for a needle in a haystack.

And that search paid off but not in the way police expected. While the man police say is the Golden State Killer was caught through a different DNA search, the Nevada DNA tests helped lead to a suspected serial killer in Colorado who police say brutally raped a young girl and then killed her and her family in 1983.

As DNA science continues to expand and more people submit their information to public DNA sites like 23andMe and others, expect to see more case results like this.

Here’s more on the police search and the surprising results.