"If she had gone to the hospital, I think that yes, she would have had a chance of survival," Perper said.

None of the medications found in Smith's blood were at radically high levels, Perper said, except for chloral hydrate. He said the sleep medication played a major role in her death.

Chloral hydrate is one of the earliest known American sedatives and gained notoriety in the 1800s as the potent ingredient in a Mickey Finn ' -- a debilitating tail of chloral hydrate and alcohol. Legend has it that the so-called ''knockout drop" was used by a Chicago bartender who slipped the substance into unsuspecting patrons' drinks and then robbed them.

The announcement comes a day before the beginning of an inquest in the Bahamas into the accidental drug overdose of Smith's son last fall, three days after Smith had given birth to a baby, Dannielynn, named in after the child's late stepbrother. A private pathologist determined that the young man had died of an accidental overdose of methadone, antidepressants, Lexapro and Zoloft.

The similar deaths had initially raised suspicions among some that Smith's longtime companion and "personal lawyer" Howard K. Stern had been somehow involved in the deaths of mother and son. He was present or nearby at both deaths.

But Seminole Police Chief Charlie Tiger said the case is closed, and that the multiagency investigation found "nothing to indicate foul play.'' Stern is expected to comment through his attorney Monday afternoon.

The autopsy results were delayed for two weeks after police found what they believed to be potentially new evidence on two laptops that belonged to Stern, but a subsequent investigation found nothing relevant to the model's untimely death, Tiger said Monday.

Smith broke the mold of the Hollywood B-lister. While other second-string celebrities faded away when their 15 minutes of fame ended, Smith kept popping up in scenarios that were hard to ignore.

There she was at the altar with a Texas oil tycoon 63 years her senior. There she was marching into the United States Supreme Court, which ruled unanimously in her favor in 2006.. But the slide into reliance on a variety of medications had already begun. Her public appearances in recent years were marked with increasingly baffling behavior and the apppearance of intoxication.

Last fall she gave birth to a baby daughter, Dannielynn, in a hospital in the Bahamas. Ex-boyfriend Larry Birkhead had been seeking a paternity test to prove he was the father of the child when Smith and Stern moved to the Bahamian island of Nassau and sought citizenship.

The child was born last September in a hospital on the island of Nassau. Three days later, in that same hospital room, Smith's 20-year-old son died of an apparently similar accidental drug overdose.

Smith was said to have been inconsolable after the death of her only son, Daniel, who was by most accounts the most cherished person in her seemingly troubled life.

But fresh controversy was right around the corner, as Smith and Stern stunned the nation's tabloid audiences when they conducted a splashy "commitment ceremony'' aboard a yacht in the Bahamas before they'd even buried her son.

One former Smith attorney said the nonbinding ceremony was simply for a "shot of emotional adrenaline" after Daniel's death. Smith and Stern were to be formally married in the Bahamas the month that she died, Stern said.

At around the same time, though, ownership of the home they had listed on their residency application in the Bahamas was being challenged by a former boyfriend of Smith's, who said he'd lent Smith his house but expected to be paid back. Smith claimed the home was a gift. That legal battle, too, is ongoing.

Then as Larry Birkhead and his then-attorney Debra Opri pressured for a paternity test on the child, several other men came forward to claim they'd fathered the child.

In a Bahamian courtroom last week, a judge ordered DNA tests on Stern, Birkhead and the baby to determine the identity of the real father. Hundreds of millions of dollars could be at stake, as Smith was fighting a years-long battle over the estate of her late husband, Texas oil tycoon J. Howard Marshall.

Stern is believed to be appealing that order, and the case is expected to be back in court next month. Meanwhile, Smith's estranged mother, Virgie Arthur, was back in the same Bahamian courthouse last week, arguing that she should be granted custody of the baby because Stern is unfit to care for the child.

Like so many other aspects of Smith's short, troubled life, the court battles could go on for some time.

By CHRIS FRANCESCANI, ABC News