The decision came after a day of testimony in the "aggravation" phase of the trial, during which prosecutor Juan Martinez hoped to prove the June 2008 killing was committed in an especially cruel and heinous manner.
Family members of victim Travis Alexander sobbed in the front row as Martinez took the jury through the killing one more time. He described how blood gushed from Alexander's chest, hands and throat as the motivational speaker and businessman stood at the sink in his master bathroom and looked into the mirror with Arias behind him.
"The last thing he saw before he lapsed into unconsciousness ... was that blade coming to his throat," Martinez said. "And the last thing he felt before he left this earth was pain."
The trial now moves into the final phase, in which prosecutors will call Alexander's family and other witnesses in an effort to convince the panel Arias should face the ultimate punishment. Arias' attorneys also will call witnesses, likely members of her family, in an attempt to gain sympathy from jurors so they give her life in prison.
The aggravation phase played out in quick fashion, with only one prosecution witness and none for the defense. The most dramatic moments occurred when Martinez displayed photos of the bloody crime scene for the jury and paused in silence for two minutes to describe how long he said it took for Alexander to die at Arias' hands on June 4, 2008.
Arias, wearing a silky, cream-colored blouse, appeared to fight back tears most of the morning. She spent the weekend on suicide watch before being transferred back to an all-female jail where she will remain until sentencing.
"She made sure she killed him by stabbing him over and over and over again," Martinez said.
The defense didn't have much of a case given how many times Alexander was stabbed, the defensive wounds on his hands, the length of the attack, and the sheer amount of blood found at the scene. Defense lawyers said Alexander would have had so much adrenaline rushing through his body that he might not have felt much pain.
The only witness was the medical examiner who performed the autopsy and explained to jurors how Alexander did not die calmly and fought for his life as evidenced by the numerous defensive wounds on his body.
Minutes after her first-degree murder conviction last Wednesday, Arias granted an interview to Fox affiliate KSAZ, only adding to the circus-like environment surrounding the trial that has become a cable TV sensation with its graphic tales of sex, lies and violence.
"Longevity runs in my family, and I don't want to spend the rest of my natural life in one place," a tearful Arias said. "I believe death is the ultimate freedom, and I'd rather have my freedom as soon as I can get it."
However, Arias cannot choose the death penalty. It's up to the jury to recommend a sentence.
The medical examiner who performed the autopsy testified Wednesday that Alexander did not die calmly and fought for his life as evidenced by the numerous defensive wounds on his body.
Arias acknowledged killing Alexander on June 4, 2008, at his suburban Phoenix home. She initially denied any involvement then later blamed masked intruders. Two years after her arrest, she said it was self-defense when the victim attacked her after a day of sex.
She stabbed and slashed Alexander nearly 30 times, shot him in the forehead and slit his throat from ear to ear, leaving him nearly decapitated before she dragged his mutilated body into his shower, where friends found him about five days later.
Prosecutors said Arias planned the killing in a jealous rage, as Alexander wanted to end their affair and planned to take a trip to Mexico with another woman.
Testimony in Arias' trial began in early January. The jury reached its verdict after about 15 hours of deliberations over four days. All 12 jurors -- eight men and four women -- unanimously agreed the killing was premeditated.
Take ABC13 with you!
Download our free apps for iPhone, iPad, Android and Blackberry devices