Experts are now concerned that Michael Jackson's use of several different doctors to obtain prescription pills and powerful drugs may have led to his death.

TMZ reports that Jackson have used aliases — among them Omar Arnold and Jack London — to obtain multiple prescriptions for drugs, including Demerol. The singer also used the name of one of his bodyguards, as well as the name of the office manager for one of his doctors.

The DEA is assisting the LAPD in investigating several doctors who prescribed drugs to Jackson.

Jackson's friend and trainer Lou Ferrigno told "Good Day LA" that Jackson was a prankster and once called and said, "This is Omar."  Said Ferrigno with a laugh, "For 10 minutes, I thought this guy was stalking me!"

More Michael Jackson dish:

Jackson camp hires top publicist Ken Sunshine

Will Michael Jackson's farewell tour start at Neverland or Staples Center?

Controversy over Michael Jackson's kids' real parents. Was his dermatologist, Arnold Klein, the sperm donor?

Lou Ferrigno was Michael Jackson's trainer?????

John Mayer compares Michael Jackson to a Rubik's Cube?

Katherine Jackson gets temporary custody of Michael Jackson's children.

Is Michael Jackson worth more dead than alive?

Posted by:Elizabeth Snead