I absolutely believe the then-21-year-old nightclub owner. That's the way it would go down. The truth will out. The guy was a tormented soul with hypnotic stage talent born in an age just technically able to create instant Western fame. Somehnow, it reminds me of Tombstone. Doc's famous epitaph for Johnny Ringo comes to mind:
"He was just too high-strung."
It sounds plausible to me as well. I read one Doors' biography that claimed Morrison had already been buried before the three other members of the band were even informed of his death.