11:15 AM PT -- TMZ has learned emergency dispatchers got a call from the prison for a heart attack, and staffers at the facility were performing CPR. They also had a defibrillator on scene.
10:25 AM PT -- The Dept. of Justice says Bulger was found at 8:20 AM, and prison staff immediately attempted to resuscitate him. Bulger had just arrived at Hazelton on Monday.
James "Whitey" Bulger -- one of America's most notorious mobsters -- was found dead Tuesday in a federal prison where he had just been transferred .