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A woman charged with killing her lover testified Wednesday that she has no recollection of stabbing him, slitting his throat or even whether she shot him during a fight at his Arizona home nearly five years ago.

Jodi Arias, 32, has spent eight days on the witness stand recounting in precise detail one life event after another -- from an abusive childhood to dead-end jobs and ex-boyfriends -- but when pressed Wednesday about how she killed Travis Alexander, she drew a blank, noting there was a "huge gap" in her memory from that day in June 2008.

Arias spent the rest of the day explaining to jurors why she repeatedly lied about her involvement in the killing, first telling authorities she knew nothing about Alexander's death, then later blaming it on masked intruders. She eventually settled on self-defense.

She said she had been contemplating suicide after she killed Alexander, and didn't want to sully his name with lurid details of their sexual relationship, given his public persona as a devout Mormon who was saving himself for marriage. She also said she was scared of being arrested, and wanted to keep up the farce to avoid suspicion.

"I just have always heard don't admit to anything," she told jurors.

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When asked about the killing, Arias said she remembers getting in a fight with Alexander, shooting at him as they tussled, putting a knife in the dishwasher and disposing of the gun in the desert as she drove from Arizona on her way to see a friend in Utah.

"I knew my life was pretty much over," she told jurors, tearfully recalling how she contemplated suicide.

"Do you remember stabbing Travis Alexander?" defense lawyer Kirk Nurmi asked.

"I have no memory of stabbing him," Arias said. "I remember dropping the knife and it clinked on the tile ... And I just remember screaming. I don't remember anything after that."

Arias said the fight started after a day of raunchy sex when she accidentally dropped Alexander's new digital camera while taking provocative photos of him in the shower of his Mesa home. She said he flew into a rage, body-slammed her and chased her around the house, coming at her "like a linebacker."

Arias said she grabbed a gun from his closet, and that it went off while they tussled. She wasn't sure if it hit him.

"I didn't mean to shoot him or anything," she said.

"He was angry at me and he wasn't going to stop," Arias added. "It was like mortal terror."

Prosecutors say she planned the killing in a jealous rage, savagely attacking Alexander in his bedroom, then dragging his body into his shower where it decomposed for five days until friends found him. He was stabbed and slashed 27 times, had his throat slit and was shot in the forehead.

Alexander's friends have said outside court that 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 is hoping the jury will spare her the death penalty with a conviction on a lesser charge -- or even an acquittal. Prosecutors must prove she planned the attack in advance to secure a first-degree murder conviction and a chance for a death sentence.

She has repeatedly denied bringing any weapons to his home. Her 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.

On Wednesday, she was asked why she didn't dial 911 after she killed him.

"I was scared. I couldn't imagine calling 911 and telling them what I had just done," Arias said. "I was scared of what would happen to me." She has yet to express any remorse for Alexander's death, but has instead repeatedly referred to her life being over -- either by suicide or arrest.

"I have a million regrets," Arias said.

Her inability to remember key facts of the killing stood in stark contrast to her previous testimony. She has recalled the exact type of flavored coffee she ordered at Starbucks in the days leading up to the attack, specific dates of sexual encounters and road trips, and in-depth accounts of stories from 10 years ago when she was just a teenager.

But as questioning finally turned to the killing, she recalled very little.

She later explained for jurors how she left Alexander's home and immediately began planning an alibi, leaving a voice mail on his mobile phone and traveling to see a friend in Utah after disposing of the gun in the desert to "throw the scent off for a little while."

She explained how she kissed and cuddled with the man she was visiting on the very day she killed Alexander, "just trying to act like myself."

"I just wanted to seem like normal, like things were OK," she told jurors. "Like I didn't just do what I just did."