Some law enforcement agencies agencies across the world are scanning people’s brains to help determine if someone has committed a crime, according to a new report from the BBC.

The technology works as a kind of “brain fingerprinting,” the BBC reported on Monday, and it’s supposedly more reliable than traditional lie-detector tests because the scans look for a specific signal that the brain emits when a person is prompted about a particularly powerful memory.

Proponents of the tests told the BBC the scans can help law enforcement determine if a suspect was directly involved in a crime, while critics said the test results could be skewed and there are still some uncertainties about the brain’s supposedly automatic response to the memories.

Scientists at Northwestern University are currently testing if it’s possible for a person to trick the brain scans by trying to forget about an event, the BBC reported, and many were successful.

Though this research is just now being performed, the BBC noted Indian police have used brain scans since 2003 and the technology has already helped render a guilty verdict in a poisoning case.