Anna Nicole Smith. Photo / Supplied.

Anna Nicole Smith. Photo / Supplied.

The judge in the trial of Anna Nicole Smith's doctors and lawyer-boyfriend said Friday he was barring all evidence linking the defendants to Smith's fatal drug overdose because they were not charged with causing her death.

Superior Court Judge Robert Perry said he fears the defendants could not get a fair trial if attorneys focused on Smith's cause of death.

Dr. Sandeep Kapoor, Dr. Khristine Eroshevich and Howard K. Stern have pleaded not guilty to conspiring to illegally provide the former Playboy model with opiates and sedatives.

Defence lawyers contend their clients did not know Smith was an addict and that they tried desperately to save the depressed model in her waning years, including a period when she gave birth to a daughter and lost her grown son to a drug overdose.

In a series of rulings during the pretrial hearing, the judge also barred admission of a videotape the prosecutor described as one of her strongest pieces of evidence. The tape, which has been broadcast on TV, shows Smith in clown makeup playing with a child.

Deputy District Attorney Renee Rose said Smith appeared "loopy" and that Stern asked if she was "on a mushroom trip."

Rose said the 10-year-old seen in the video would testify she saw Stern give Smith liquid medicine from a bottle. But the judge noted that prosecutors don't know what was in the bottle and don't have a prescription linked to it.

Perry also barred a taped TV interview of Smith when she left the Betty Ford Center after treatment for drug and alcohol addiction in 1996. He said it was too far removed in time from events involved in the trial.

"For you to say this lady was loaded on drugs for 10 years before these people came along -- I don't know how this helps your case," the judge told Rose. He said jurors could be told Smith had undergone treatment at the center.

Perry also said he doesn't understand why the case was not filed in Florida, where Smith died in 2007.

Prospective jurors are set to return to court Monday for in-depth questioning, with opening statements scheduled Wednesday in the trial expected to last three months.

- AP