Whitey Bulger’s death has officially been ruled a homicide.

The notorious gangster died of “blunt force injuries to the head” after being assaulted by multiple people, according to his death certificate, obtained by NBC10 Boston on Thursday.

Bulger, 89, was bludgeoned to death with a padlock stuffed in a sock Oct. 30, 2018, hours after being transferred to a federal jail in West Virginia.

Officials have said they believe other inmates killed the blood-thirsty Boston gangster. Six months after his murder, no one has been charged.