Michael Jackson Doctor -- MIA

We've learned law enforcement is looking for a doctor who lived at Michael Jackson's home -- and the doctor is nowhere to be found.

Law enforcement sources tell us a BMW belonging to the doctor was towed from Jackson's home last night.

Cops are looking to interview the doc.

A law enforcement source says the doctor gave Jackson an injection before he died.

Jackson reportedly may have OD'd on Demerol. As we first reported, family members were concerned that Jackson was taking too much morphine.