James “Whitey” Bulger, who lived a double life as one of Boston’s most notorious mobsters and as a secret FBI informant before going on the run for 16 years, has been found dead at a federal prison in West Virginia.

The Federal Bureau of Investigation is looking into Bulger’s death and a prison employee briefed on the matter said it is being investigated as murder.

The US Justice Department paid more than $20m in damages to families of people killed by Bulger on the grounds that he was operating under government supervision while killing.

-Noah Harte