Cocaine caused the heart attack that killed the Who's bassist John Entwistle, a coroner reported Thursday.

The Las Vegas medical examiner also classified the death as accidental and not due to an overdose, according to the Associated Press. How much cocaine was in Entwistle's system couldn't be determined, however.

The drug caused his coronary arteries — already damaged by a pre-existing heart condition — to contract, which led to the fatal heart attack.

The 57-year-old's body was found June 27 in his hotel room at the Las Vegas Hard Rock Hotel and Casino, a day before the Who were to begin a three-month tour at the hotel's venue (see [article id="1455460"]"John Entwistle, Bassist For The Who, Dead At 57"[/article]).

The originally scheduled tour kickoff was postponed in the wake of Entwistle's death, but the two surviving founding members, Roger Daltrey and Pete Townshend, along with a session bassist filling in for the departed Ox, continued with their tour plans July 1 in Hollywood, California (see [article id="1455912"]"The Who, Fans Join Together At 'Very Difficult' Tour Kickoff"[/article]).