Murderers can be tracked down using ancestry websites under a new technique developed by Stanford University scientists.

Detectives in California have already used a public ancestry database to arrest Joseph James DeAngelo, the alleged Golden State Killer, who is believed to have committed at least 13 murders and more than 50 rapes.

However, Stanford’s new computational tool could speed up investigations and make them much easier.

It works by providing new ways for police forensics databases - which can often be patchy - to be used alongside the wealth of data contained in public gene databases, such as Ancestry.com and 23andMe.

These are used by consumers who send in their own DNA samples for analysis to discover more about their family history.

The data on these sites is so large that experts believe it’s possible to use them to identify six in every 10 people in the US who are of European descent, even if they have never provided a DNA sample.

Creating the new tool was a technical feat because the two databases use completely different systems of genetic markers.