Anna Nicole Smith's romantic partner, longtime lawyer and alleged father of her infant daughter provided her son with one of the drugs that killed him — then tried to cover it up by flushing the remaining pills down the toilet, a report says.

The charges surfaced Monday as Bahamian officials agreed to conduct a formal inquest into the death of 20-year-old Daniel Smith in his mother's hospital room there in September, sources told the celebrity Web site TMZ.com.

More than 20 witnesses will be called to testify, including one who allegedly insists that Howard K. Stern gave Daniel methadone before he died.

Stern was in the room at the time of Daniel's death.

Methadone is one of at least three drugs that made up the lethal cocktail that led to Daniel's heart attack, according to an autopsy report.

The same witness also will tell officials that after Daniel's death, Stern flushed the remaining methadone down the toilet, TMZ reported.

Smith will also be among the witnesses required to testify before the jury inquest, Chief Magistrate Roger Gomez said.

"It's to try and answer all the unanswered questions that have been raised in this matter," he told reporters.

The inquest at the coroner's court will be open to the media, he said.

Smith, 39, and Stern, 38, exchanged vows in a non-marriage "commitment ceremony" 18 days after Daniel died on Sept. 10 in her hospital room in the Bahamas, where she had given birth to a daughter three days earlier.

Meanwhile, a judge has given Smith, a former Playboy Playmate and reality star, until Jan. 23 to have her infant daughter undergo paternity testing sought by a former boyfriend.

Smith's ex-boyfriend Larry Birkhead claims he's the father of Dannielynn Hope Marshall Stern.

Birkhead, 32, sued in October to get a paternity test. Stern maintains he is the baby's father.

The New York Post's Kate Sheehy contributed to this report.

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