Whitney Houston's preliminary autopsy results have reportedly revealed that sedatives were in the singer's system.

The legendary star passed away at the age of 48 on Saturday afternoon. Whitney's lifeless body was found in a fourth-floor hotel room in Beverly Hills, with no immediate apparent cause of death. However, it was claimed that prescription drugs including Lorazepam, Valium and Xanax were found in Whitney's room.

Los Angeles County Coroner Assistant Chief Ed Winter says the results of the preliminary tests could be made public this week, which will determine if the drugs were indeed in Whitney's body at the time of her death.

Sources say the results - which haven't been publicly disclosed yet - will show that sedatives were found in Whitney's system.

"The preliminary results indicate that there were benzodiazepines present in Whitney's system," a law enforcement insider told RadarOnline.com. "The final toxicology results will reveal the specific sedative(s) that she ingested, and the level. Those final toxicology results should be in later this week.

"Toxicology testing and results don't take four to 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."

Meanwhile, a source on the set of Whitney's final film Sparkle has revealed the singer seemed healthy during filming.

The insider added the star's passing was even more shocking because of her positive demeanour.

"Whitney was in good shape and there weren't any major issues with her," a source told e! Online.

Sparkle's producer Bishop T.D. Jakes released a statement following news of Whitney's death.

"We are deeply saddened by the tragic and untimely passing of Whitney Houston, whom we were blessed to have just completed work with on the remake of the film Sparkle. We ask the world to join us in lifting up Whitney's family in prayer and ask God for their strength and comfort during this devastatingly difficult time," he said.

"At the apex of her career, Whitney had no peer, with a voice that shaped a generation. She has left behind a musical and film legacy that will endure.... she will be sorely missed by us all, B."

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