Preliminary autopsy results have revealed sedatives were found in Whitney Houston's system after she died.
The tests have reportedly shown that the 48-year-old singer had taken sedatives, particularly benzodiazepines, before she was found dead in the bathtub of her Beverly Hills hotel room on Saturday (11.02.12).
A law enforcement insider told RadarOnline.com: ''The preliminary results indicate that there were benzodiazepines present in Whitney's system.
''The final toxicology results will reveal the specific sedatives that she ingested, and the level. Those final toxicology results should be in later this week.
''Toxicology testing and results don't take four-six weeks to come back. Look at how quickly toxicology screening tests are done in hospital emergency rooms when someone comes in with an overdose.
''The Coroner and the Beverly Hills Police Department have placed a security hold on the case, so it will be a few weeks before the results are revealed publicly.''
Los Angeles Police were said to have found prescription pill bottles of Xanax, lorazepam, and valium - which are all benzodiazepines - as well as Ibuprofen, Midol and Amoxicillin in the fourth-floor suite of the hotel.
Detectives investigating Whitney's tragic death are set to question up to nine doctors as they aim to find out why the mother-of-one - who had a history of drug and alcohol abuse - could get hold of such a large quantity of substances.
A postmortem examination on her body was carried out on Sunday (12.02.12) but no definitive answers about the 'I Will Always Love You' hitmaker's cause of death were given.
Whitney's funeral is set to take place on Friday (17.02.12) in Newark, New Jersey.
A golden hearse took her body from Teterboro airport to the Whigham funeral home under heavy police escort last night (13.02.12).