MARTINEZ, Calif. — The honeymoon is over.

Murder defendant Susan Polk capped a fifth day of unusually congenial testimony by slamming her palm on the witness stand, starting a shouting match with the prosecutor, and being given a time-out by the judge.

"I move for a mistrial based on being called a liar!" Polk said during a sidebar Wednesday.

The motion was denied.

"He's a name-caller and a baby," Polk said, pointing at Assistant District Attorney Paul Sequeira.

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Polk, 48, is representing herself against the charge of first-degree murder of her 70-year-old husband, psychologist Felix Polk.

Her confrontational behavior in court since trial began March 7 has caused numerous delays and time-outs, but since Polk took the stand last week, she has been gentle with opposing counsel and cooperative with the judge.

Her outbursts Wednesday occurred after Sequeira objected to her attempts to tell the jury that Felix molested his daughter from a previous marriage.

"I have talked to this young woman," Sequeira told the judge. "I have a good-faith belief that the defendant was fabricating this and she's saying it in front of the jury and in front of the media."

Polk claims Jennifer Polk wrote letters to her father that refer to inappropriate behavior.

"My husband said he was afraid of being accused of all-out sexual abuse by her," Polk said. "Given his conduct with me, it's likely he sexually abused her."

Polk was previously warned that such testimony was off-limits until she presented evidence for the court's review and waited for rulings on admissibility.

Polk told the judge that most of the letters are missing because someone stole her "Jennifer file."

"I was impressed that we have gone for four days very smoothly," Judge Laurel Brady told Polk.  "But this display in front of the jury with such a sensitive matter, especially when I'm learning for the first time that those letters just don't exist anymore, is ..."

"That's not true!" Polk interjected.

"... is just outrageous. Stop interrupting me. I'm not done!" Brady said sternly.

"You know very well I said none of this subject matter is coming in before I reviewed it," Brady scolded Polk. "I don't believe for a minute that you misunderstood what I meant."

Polk has been testifying in a narrative style from the witness stand for more than 17 hours. She has been given wide latitude to read to jurors from her diaries, letters and other documents that speak to her rocky 30-year relationship with her therapist-husband.

Polk admits she stabbed Felix with a paring knife in October 2002 at the tail end of a bitter divorce, however, she claims she acted in self-defense after he attacked her. A defense expert witness testified that Felix died of a heart attack, not his multiple stab wounds.

"It is an outrageous abuse of your power to keep me silent on his abuse!" Polk yelled as the judge stepped away from the bench.

"Nobody's going to keep you silent," Sequeira said under his breath.

The jury was sent home early after Polk refused to stop arguing with the judge.

Polk will continue her direct testimony Thursday, and Sequeira may begin his cross-examination by the afternoon.

At Polk's request, attorney Gary Wesley will be allowed to advise her during her cross-examination.

In a unique compromise ruling, Brady announced that she would allow Wesley to sit in a chair behind the witness stand, so Polk could confer with him during questioning.

Wesley would serve only an advisory role, Brady said, and any legal objections or defense decisions would be solely made by the defendant.

Polk was alone at the defense table at the end of court Wednesday when her case manager Valerie Harris approached to inform her that her son, Eli Polk, was convicted in a separate matter in a courtroom across town.

Eli, 20, is the only one of Polk's three sons to testify in her defense.

Polk and Harris spoke in whispers about the decision. Polk appeared concerned but did not immediately show any emotion.

Eli was arrested in March after an altercation with an ex-girlfriend that occurred in the same home where his father died.

According to sources close to the case, Eli rejected a plea bargain at his mother's urging, opting to go to trial to fight six counts, including misdemeanor battery, dissuading a witness and violating a restraining order.

Unlike his mother, Eli chose to be represented in court by his public defender.

The jury found Eli guilty of three of the six counts, including one count of battery and two counts of violating a restraining order.

He was sentenced to nine months in prison.

Polk faces 25 years to life if convicted of the murder of her husband.