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A woman charged in the stabbing and shooting death of her Arizona lover traded barbs with a prosecutor Thursday under a withering cross-examination as she struggled to explain why she can recall precise details of her life from years earlier, yet can't remember crucial aspects of the murder case against her.

Jodi Arias, 32, faces a potential death sentence if convicted of first-degree murder in the June 2008 killing of Travis Alexander in his suburban Phoenix home. She was testifying for a ninth day Thursday as the prosecution began its cross-examination, hammering her with questions about her apparent selective memory.

Questioning grew so heated that the judge admonished Arias and prosecutor Juan Martinez to stop talking over each other. Arias smirked at times while Martinez stammered in frustration.

Alternating between tears and poise, Arias has testified in painstaking detail about the events that led her to kill Alexander, she says in self-defense.

Yet when asked for details from the day of the killing, she didn't recall much.

"Do you have memory problems, ma'am?" Martinez asked.

"Sometimes," Arias replied.

Martinez hammered back, noting it's puzzling that she can't remember such crucial details to the case, yet "can tell us what kind of coffee you bought at Starbucks sometime back in 2008."

"When do you have memory problems? Martinez asked, raising his voice.

"Usually when men like you are grilling me and screaming at me or men like Travis," Arias replied calmly.

Martinez also questioned her contention that she was monogamous throughout her relationship with the victim while referring to Arias' previous testimony that the day she killed him, she went to visit a man in Utah and slept in his bed, kissing and cuddling.

She said she didn't know Alexander was dead when she left his home, noting her memory from that day has "huge gaps."

"At that point you didn't know, according to your own story, that Mr. Alexander was dead, right?" Martinez snapped.

"I guess I knew. I just wasn't expecting it," Arias said softly. "I wasn't really in my own mind."

"Make up your mind, please," Martinez responded sharply.

Arias testified on Wednesday she recalled little about the day of the killing. She remembers Alexander in a rage, body slamming her and chasing her around his home.

She said she grabbed a gun from his closet, and it went off, but she wasn't sure if she shot him. She had no explanation for his 27 stab wounds and slit throat. He had been shot in the forehead.

Arias also attempted to explain away her repeated lies. She first told authorities she knew nothing about Alexander's death, then later blamed it on masked intruders before eventually settling on self-defense.

She said she was scared of being arrested, had been contemplating suicide and didn't want to sully Alexander's name with accounts of his violent behavior and lurid details of their sexual relationship, given his public persona as a devout Mormon who was saving himself for marriage.

Martinez also hammered her Thursday on other changing stories. Arias claims she injured her right finger when Alexander beat her months before the killing, even once holding up her crooked digit in a dramatic display for jurors in previous testimony.

However, Martinez noted Arias told a detective after her arrest that she injured her finger on the day of Alexander's death when one of the intruders attacked her.

"You gave him a different story," Martinez said pointedly.

"Yes," Arias replied.

"Then you testified about it in this court and you gave us another story of how this happened, right?" Martinez asked.

"No," Arias said defiantly.

Martinez noted that Arias made no mention of injuring her finger in a fight with Alexander in her journal where she kept pages of intimate details from her life.

"And no one knew about this supposed or claimed injury to your finger until after you killed Alexander, right?" he said.

"That's right," Arias replied.

Prosecutors say Arias planned the killing in a jealous rage, savagely attacking Alexander in his home.

Alexander's friends say Arias is lying about her contention that he had sexual desires for young boys, and that he was physically abusive, and no witnesses have testified of any previous violent behavior. Authorities also have said they did not believe Alexander owned a gun, and there has been no testimony to back up Arias' story that he kept one in his closet.

Arias' grandparents reported a .25 caliber handgun stolen from their Northern California house about a week before the killing -- the same caliber used to shoot Alexander -- but Arias claims to know nothing about the robbery. She says she brought no weapons to Alexander's home on the day she killed him.

Prosecutors must prove she planned the attack in advance to secure a first-degree murder conviction and a chance for a death sentence.

Of the day she killed Alexander, Arias says she only remembers shooting at him, putting a knife in the dishwasher and disposing of the gun in the desert as she drove from Arizona on her way to Utah. And she immediately began planning an alibi "to "throw the scent off for a little while."