HOUSTON, Texas (AP) -- Andrea Yates once advised a fellow inmate that she could escape prosecution by pretending to be mentally ill and persuading a psychiatrist she suffered from serious disorders, according to court documents filed Thursday by prosecutors.

Felicia Doe, who spent four days in a jail block with Yates in 2002, told prosecutors last year that Yates instructed her not to eat, not to speak properly and not to be friendly or open in front of people if she wanted to "beat her case."

Yates, who is awaiting a new trial in the drowning of her young children, allegedly told Doe that if she could get the jail psychiatrist on her side, they could testify to her mental health, and they couldn't prosecute her if she was sick, according to the documents, which describe interviews with witnesses who could be called during Yates' trial.

Defense: 'Bogus' story
"According to the witness, the defendant basically told her, 'Do what I'm doing,"' prosecutor Kaylynn Williford wrote.

Yates' defense attorney, George Parham, called the account "sad and ludicrous."

"That is absolutely so bogus, it doesn't even deserve a response," he said. "That discounts the medications that this woman was on, the mental illness she suffers from."

Yates, 41, has pleaded innocent by reason of insanity.

During her 2002 trial, psychiatrists testified Yates suffered from schizophrenia and postpartum depression, but expert witnesses disagreed over the severity of her illness and whether it prevented her from knowing right from wrong.

A jury rejected Yates' original insanity defense and sentenced her to life in prison for the drowning of three of her five children ages 7, 5 and 6 months. Evidence was presented about the drowning of two others, ages 3 and 2, but Yates was not charged in their deaths.

Convictions overturned
Her convictions were overturned last year based on false testimony by an expert witness.

Doe, who could not be reached for comment, also told prosecutors that Yates disclosed details of the slayings, explaining that she locked a door so her oldest son, 7-year-old Noah, could not escape the house and describing him as crying so hard he vomited.

"She hit his head against the bathtub several times in an effort to incapacitate him," Doe told prosecutors.

Another inmate, Lynnette Licantino, told prosecutors Yates said her children "were just too much" and that her husband at the time, Russell Yates, would not let her put them in day care, according to the documents.

Licantino could not be located for comment.

Yates' trial is set to begin March 20.