The autopsy on former "American Idol" contestant Michael Johns has been completed, but the medical staff at the Orange County Coroner's Office is deferring the cause of death ... pending toxicology results.
TMZ first reported ... Johns had sprained his ankle and the swelling spread up to his knee. He went to the doctor Thursday ... the day before he died. We're told he was in great pain.
Law enforcement sources tell TMZ ... the police were informed Johns had engaged in heavy alcohol use at some point prior to his death. And we're told he was a heavy drinker.
One law enforcement source tells us ... it would be fairly routine if the doctor who saw Johns on Thursday prescribed pain meds.
If there was a blood clot, it would appear it was not clearly the cause of death ... or else the case would be closed. The fact that toxicology tests are being performed suggests the Coroner wants to know if alcohol and/or drugs played a part in Johns' death.
By the way ... there's a condition called deep vain thrombosis -- a blood clot that forms deep in the body. The swelling from Johns ankle to his knee is consistent with the condition, but so far the Coroner has not concluded that was the cause of death.