Martin MacNeill Trial: Expert Witness Says Utah Doctor's Wife Died of Drowning

Nov. 1, 2013— -- Though her husband is on trial for her murder, a cause of death has never been determined for Michele MacNeill. Today, a noted forensic pathologist and toxicologist testified that he believes the former beauty queen died as a result of drowning.

Dr. Joshua Perper, a retired medical examiner who was called as an expert witness at the murder trial of Dr. Martin MacNeill, said that not only did he believe the mother of eight was drowned, but drugs could have also played a role in her April 11, 2007 death.

"It was clear she was inhaling a significant amount of water," Perper said.

He said the report that MacNeill regurgitated more than seven cups of water during the resuscitation process also played a role in helping him reach his conclusion.

"In addition, she had some drugs on board [that] in my opinion, could have contributed to her death," he said.

Dr. Martin MacNeill, 57, is on trial for the April 11, 2007, death of his wife, Michele MacNeill, 50. Prosecutors allege MacNeill persuaded his wife to have plastic surgery so he could dope her up during her recovery and then drown her -- all so he could pursue a relationship with a mistress, Gypsy Willis.

MacNeill's defense lawyers said heart problems were a contributing factor in her death. Perper said his review of MacNeill's case found no evidence that she died of myocarditis, an inflammation of the heart.

Utah State Chief Medical Examiner Dr. Todd Grey testified on Thursday that a drowning scenario was possible.

Dr. Maureen Frikke, a former assistant medical examiner who died in 2008, certified that MacNeill died of cardiovascular disease, high blood pressure and inflammation of the heart. That report was amended after Grey reviewed the case after Frikke's death and changed the ruling to "undeterminable."

Despite the amended report, Grey told the court, "I did not feel I could reach a conclusion of homicide."

Doctor's Daughter Confronted Him About Over-Medicating Mom

In the days before Michele MacNeill was found lifeless in the bathtub, one of her eldest daughters, Alexis Somers, confronted her dad about allegedly over-medicating her mom as she recovered from plastic surgery.

After Alexis Somers found her mother "very sedated" one day after she came home from the hospital on April 4, 2007, Somers, who was then a medical student, said she told her father, Dr. Martin MacNeill, "I'm taking over."

Somers said her mother was a reluctant plastic surgery patient who didn't like taking all of the drugs her physician husband insisted she take during her recovery.

Watch the Full '20/20' Report: Life of Lies

After taking a cocktail of pills that left her sedated, Somers said her mother told her she no longer wanted MacNeill to dispense her medication since she couldn't see through the bandages on her face.

"She actually had me take out every single pill from the pill bottles and she wanted to feel what the pills feel like in her fingers, so if my dad tried to give her anything, she would know what he was giving her," Somers said.

On April 10, 2007, Somers said she left her family's home in Pleasant Grove, Utah, to go back to medical school in Henderson, Nev.

Somers told the court her mother "was feeling really well" when she left.

The next day, the mother of eight was found by her 6-year-old daughter unconscious in a bathtub full of brown water. Less than two hours later, Michele MacNeill was dead.

The trial, which is in its third of five scheduled weeks, has played out like a soap opera in the court room.

Willis, the mistress who prosecutors allege was MacNeill's motive for murder, testified that she moved into the family's home days after Michele MacNeill's death and that she was hired to work as a nanny.

Four of MacNeill's daughters told the jury that Willis never looked after the children, and instead was "goo eyes" at their father, who months later, proposed to her with a four and a half carat diamond ring.