The legendary metal troubadours in Metallica are helping the FBI in their search for a killer. Frontman James Hetfield has even filmed a public service announcement appealing to Metallica fans for help.

The PSA hopes to elicit information about a man suspected of murdering Morgan Harrington, a Virginia Tech student. Harrington's body was found near an arena in Charlottesville, Virginia shortly after the group's concert there in 2009.

The FBI have linked DNA found at the scene with a 2005 sexual assault in Fairfax City. Crime Stoppers has offered $100,000 for information leading to an arrest, and Metallica has offered $50,000.

The PSA includes a police sketch of the suspect and a heartfelt plea from Hetfield.

"Remember, any information – no matter how small you might think it is – could be that crucial piece investigators need to help solve the case," he says.

Check out the video below for more details.