Former Playboy Playmate Anna Nicole Smith died of an accidental drug overdose, autopsy results show, authorities confirmed Monday.

"We have reviewed hundreds of hours of video tape captured by the hotel's security cameras and we found nothing unusual. We analyzed contents of the laptop computer belonging to (her companion Howard K.) Stern and we saw nothing to indicate any foul play," Seminole Police Chief Charlie Tiger said in Fort Lauderdale, Fla. on Monday.

"We are convinced, based on an extensive review of the evidence that this case is an accidental overdose with no other criminal elements present," Tiger told reporters.

The autopsy results effectively closes the case on the death of Smith, the police chief added.

Smith had a cocktail of prescription drugs in her body when she died, including Valium, Ativan, and Methadone, Broward County Medical Examiner Dr. Joshua Perper told reporters.

She died of "combined drug intoxication" with the sleeping medication chloral hydrate as the major factor, the medical examiner said.

Chloral hydrate is a sedative used to treat insomnia and alcohol withdrawal, relieve anxiety and ease post-surgery pain. Smith had been taking several anti-depressant and anti-anxiety drugs before she died, Perper said.

A bacterial infection from injecting medication in her buttocks and a viral infection contributed to her death, the autopsy report said.

Smith felt ill shortly after arriving in Fort Lauderdale from the Bahamas on Feb. 5 and eventually developed a fever of 40.5 C (105 F). The medical examiner said Smith had a blood infection likely caused by a contaminated needle but it was quickly brought under control by antibiotics and an ice bath.

"Her temperature never went again above 100 (37.8 C) and, except for an episode of vomiting, she felt relatively well expect for feeling very weak,'' he said.

Smith was found unresponsive in a hotel in Hollywood, Fla. on Feb. 8.

Unknown additional evidence from the Seminole Police Department delayed the autopsy's release.

The department is probing the former model's death because the Seminole Hard Rock Hotel and Casino, where she was staying, is located on tribal land.

No serious injuries were revealed in the initial examination conducted by Perper.

Perper's initial tests found no evidence, either in Smith's stomach or her bloodstream, that she had taken large amounts of prescription medication.

The medical examiner said prescription drugs, but no illegal drugs, were found in Smith's hotel room. He wouldn't identify the drugs.

The initial examination also found signs of inflammation in Smith's heart. Perper said it was "something which looks a little bit unusual" but also noted "may be nothing."

Smith arrived at the Hard Rock on Feb. 5 and planned to leave four days later aboard a new yacht that her companion Howard K. Stern was arranging to buy.

She was seldom seen outside her room during her stay.

Smith was said to be suffering from a stomach flu before she was found dead.

Smith's 20-year-old son Daniel died under suspicious circumstances five months before his mother. An inquest into his death is scheduled to start Tuesday.

Smith was a Texan who went from topless dancer to Playboy Playmate of the Year, Guess jeans model and bride of 89-year-old oilman J. Howard Marshall II.

She took her battle for his estimated US$500 million estate as far as the nation's top court. The ongoing legal dispute could make her daughter Dannielyn very wealthy.

Several men, including Stern and former boyfriend Larry Birkhead, are claiming they fathered Dannielynn.