Michael Jackson waves to supporters as he leaves the Santa Barbara County Courthouse after he was found not guilty in Santa Maria, June 13, 2005. REUTERS/Gene Blevins

Pop star Michael Jackson's death was caused by lethal levels of the powerful anesthetic propofol, according to findings by the Los Angeles chief medical examiner unsealed in court documents in Houston on Monday.

Jackson suffered cardiac arrest and died on June 25 at age 50. Since then, police have probed his death in an investigation that appears focused on the use of prescription drugs and the role of doctors who treated him, including his personal doctor, Conrad Murray.

The Los Angeles Chief Medical Examiner-Coroner, Dr. Sathyavagiswaran, indicated that he had reviewed the preliminary toxicology results and his preliminary assessment of Jackson's cause of death was due to lethal levels of propofol (diprivan), according to a search warrant affidavit for Murray issued by California.

The document was released by the Harris County District Clerk in Houston, where Murray has offices, which U.S. Agents raided on July 22, looking for evidence of manslaughter.