Pop star Michael Jackson's death was a homicide caused by prescription medications, the Los Angeles County coroner's office announced on Friday.

Jackson died of acute propofol intoxication -- a powerful sedative -- and the effects of the anti-anxiety drug lorazepam, the office said in a final ruling.

Other drugs found in Jackson's system were midazolam, diazepam, lidocaine and ephedrine, according to the office's investigation.

The coroner's report remains under seal pending the completion of a Los Angeles Police Department (LAPD) investigation into the singer's death.

Also on Friday, the LAPD said state and federal drug-enforcement agencies are conducting separate investigations into issues that " may not be directly related to the cause of death."

LAPD officials said their investigation was ongoing "and will result in the case being presented to the Los Angeles County District Attorney for filing consideration."

Jackson died June 25 at his rented Holmby Hills mansion in Los Angeles at age 50, just days before he was to perform a series of concerts in London.

Jackson's doctor Conrad Murray told investigators that he had given Jackson the drug early the morning of his death, according to the earlier warrant.

He said he had given him the medication in the past, but was trying to wean him off of the drug, fearing that he was developing an addiction.

Murray said he gave Jackson a series of medications over the course of that night because the singer could not sleep.

According to court documents, Jackson repeatedly demanded the propofol, which he referred to as his "milk," and Murray finally agreed.

Murray told investigators he left Jackson for about two minutes to go to the bathroom, and when he returned, he found Jackson not breathing.

Investigators are trying to determine if charges are warranted against Murray or other doctors who may have prescribed or administered the medication, which is usually used only in hospitals during surgery.

Murray's home in Las Vegas and offices in Nevada and Houston have all been searched in recent weeks by Los Angeles police and federal agents. Previous court filings from those searches indicated that investigators were conducting a manslaughter investigation.

Murray has denied any wrongdoing, saying he did not administer any medications that should have led to the singer's death.

Murray's attorney, Edward Chernoff, issued a statement on Friday, saying the coroner's announcement is "nothing new," and questioned why any announcement was made while the autopsy remained sealed.

"In any case, this has all the earmarks of police gamesmanship, and we will not be responding until we get a full autopsy report, including the entire list of drugs found in Mr. Jackson, their quantities and all other data that would allow independent medical experts to analyze and interpret."

Meanwhile, Jackson's family issued a statement, saying :

"The Jackson family again wishes to commend the actions of the coroner, the LAPD and other law enforcement agencies, and looks forward to the day that justice can be served."

(Xinhua News Agency August 29, 2009)