Model's death remains a mystery

Smith's life and death have drawn comparisons to Marilyn Monroe's

An initial autopsy has failed to find the cause of former top model Anna Nicole Smith's death.

But medical examiner Joseph Perper said he had not ruled out an overdose as a cause, and was waiting for the results of chemical analysis.

Ms Smith, 39, who fought a long battle for the estate of her late oil tycoon husband, died on Thursday.

Attention is now focusing on a battle between three men over the paternity of her five-month-old daughter Dannielynn.

'Medical puzzle'

Seminole Police Chief Charlie Tiger told journalists that there was "no evidence" to suggest that Ms Smith's death was the result of a crime.

Smith is said to have been heartbroken at the death of her son

But he said the investigation would remain open until Dr Perper, the Broward County medical examiner, completed his investigation.

Dr Perper said that could take from three to five weeks.

"It is a medical puzzle which we have to resolve to get a comprehensive picture of what happened," he said.

He said DNA samples had been taken from the fomer Playboy model.

"In every case in America, the examiner's office takes samples," he said.

Custody battle

Ms Smith died only five months after the birth of her daughter.

Three men are now claiming to be the father of the child, who is potentially heir to a multi-million-dollar fortune.

Ms Smith married Texas oil billionaire J Howard Marshall II in 1994, not long after being named Playboy's Playmate of the Year. She was 26 and he was 89.

It is a medical puzzle which we have to resolve to get a comprehensive picture of what happened Dr Joseph Perper Life in pictures

He died 14 months later, setting the stage for a battle over his estate that pitted Ms Smith against Marshall's son.

The case has not yet been resolved, even though Marshall's son died last year.

Ms Smith's own son Daniel died in September, leaving her daughter as her only surviving offspring.

Both Ms Smith's lawyer and partner, Howard K Stern, and her ex-boyfriend Larry Birkhead say they are the father of the baby.

Ms Smith said Mr Stern was the father, but Mr Birkhead was demanding DNA testing even before Ms Smith died.

The husband of Zsa Zsa Gabor, Prince Frederick von Anhalt, also says he may be the father.

A judge has ordered that Ms Smith's body be preserved until a paternity hearing later this month.