LOS ANGELES >> The Los Angeles County coroner’s office has issued subpoenas for medical and pharmacy records from Whitney Houston’s doctors and medical providers, which is standard procedure in such investigations, an official said.

Assistant Chief Coroner Ed Winter said the request is made in virtually all death investigations because it can shed additional light on how people died and whether they had any serious medical conditions.

"We’ve already contacted a number of doctors with requests for records," he said.

Winter said that at this point, there is nothing unusual about how his office is proceeding with the Houston death investigation and that requests for medical records are requested through subpoenas.

"If somebody even dies in a crash, a blunt force trauma, we will still take medical issues into account," he said.

"Anything helps."

Investigators in the Houston case found several bottles of prescription medication in the Beverly Hills, Calif., hotel room where she died Saturday, although Winter has said they weren’t an unusually large number. Detectives have declined to disclose which medications were seized.

Authorities said an autopsy found no indications of foul play or obvious signs of trauma on Houston. She was underwater and apparently unconscious when she was pulled from a bathtub, officials said.

It could be weeks before the coroner’s office completes toxicology tests to establish the cause of death.

Medical records have become crucial in celebrity death investigations, including inquiries into what killed actor Corey Haim, actress Brittany Murphy and pop superstar Michael Jackson. Haim’s death was caused by pneumonia and not drug-related, the coroner’s office ruled. Prescription medications were cited as a contributing factor in Murphy’s death, which coroner’s determined was caused by pneumonia and severe anemia. Murphy, who was ill in the days before she died in December 2009, showed no signs of drug abuse, a coroner’s report stated.

In Jackson’s case, state and federal investigators spent months looking into Jackson’s medical history and doctors who had prescribed him medication. They decided not to file charges against seven doctors who treated Jackson, although they referred one unnamed physician to the state’s medical board for prescribing medications to Jackson under an alias.

Jackson’s personal physician, Conrad Murray, was convicted of involuntary manslaughter for the singer’s death. He had been giving the entertainer nightly doses of the anesthetic propofol in Jackson’s bedroom as a sleep aid but kept no records of the treatments.

Prosecutors and experts said during Murray’s trial that his decision not to keep records was reckless and deprived Jackson’s family from having a full account of how he died.

Law enforcement can access California’s prescription drug monitoring database known as CURES, which contains more than 100 million prescriptions and receives anywhere from 4 to 6 million additions every month. The data culled from pharmacies can determine whether doctors are prescribing outside the course of normal medical practice and see if a patient is getting multiple prescriptions from various physicians, commonly known as doctor shopping.

Gov. Jerry Brown touted the CURES program several years ago when he was attorney general, and under his leadership high-profile investigations were launched into the deaths of Jackson, Haim and Anna Nicole Smith.

In the Smith case, charges eventually were filed against two doctors and her boyfriend-lawyer in connection with her death after the database showed the former Playboy Playmate was receiving a myriad of prescription drugs. A jury acquitted the trio of most to all of the felony counts and a judge dismissed two convictions, while reducing one to a misdemeanor.

Houston died just hours before she was scheduled to appear at producer Clive Davis’ pre-Grammy Awards bash.

Her family plans a private church service in her hometown of Newark, N.J. The Associated Press will provide a pool camera and stream the service on livestream.com/aplive, said Houston’s publicist, Kristen Foster.

Houston, a sensation from her first, eponymous album in 1985, was one of the world’s best-selling artists from the mid-1980s to the late 1990s, turning out such hits as "I Wanna Dance With Somebody," ”How Will I Know," ”The Greatest Love of All" and "I Will Always Love You." But as she struggled with drugs, her majestic voice became raspy, and she couldn’t hit the high notes.

Interest in her music has skyrocketed since her death, pushing her songs back on to charts and into heavy rotation on the radio.

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Associated Press Writer Greg Risling contributed to this report.