They will decide if Arias, 32, planned to kill her lover, Travis Alexander, whether it was an act of self-defense, or an act of rage. Arias is charged with first-degree murder; if that is what the jurors decide she did, then they will also have to decide if she should be sentenced to life in prison or to death.
"Do you go on vacation to sacred Mormon sites with your stalker?" he asked while showing snapshots of Arias and Alexander posing cheek to cheek and smiling. "How scared is he?"
The jurors spent the last three days of trial reliving an intense and dramatic anatomy of a murder.
Wednesday was an unprecedented 11 1/2-hour hearing at which experts for the defense and the prosecution discussed whether Arias suffered from borderline personality disorder or post traumatic stress disorder, and whether Alexander could have gotten up and fought with Arias after being shot in the head.
Alexander, 30, was killed in June 2008. His decomposing body was found in the shower of his Mesa home with nearly 30 stab wounds, a gunshot to the head and a slit throat. The sequence of the wounds has been a matter of dispute.
For four years after the murder, the prosecution theorized that Arias first shot Alexander, then stabbed him as they fought, then slit his throat. But days before jury selection began last December, prosecutor Juan Martinez announced that Arias had first stabbed Alexander, then slit his throat and then shot him in the head after he was already dead, a scenario that sounds colder and crueler.
The medical examiner who performed Alexander's autopsy testified twice to say that he did not believe Alexander would have been able to move about after being shot in the head, leading Martinez to conclude that the stabbings were first.
But on Wednesday, a neuropsychologist testified for the defense that he had worked with at least two patients who had survived projectile wounds to the brain's frontal lobe and neither had been rendered unconscious. Martinez then produced the medical examiner for a third time to aver that it was not possible.
A juror asked him the question the attorneys had not thought of: Isn't it true that 100 percent of the people the medical examiner saw with such wounds were already dead?
Yes, he said.
Martinez made his closing arguments Thursday. Over the course of the day his voice rose in high sarcasm or dropped to an empathic whisper as he addressed the jury. He painted Arias as a gold digger who "preyed on Mormon boys" because they were hard-working and successful. He downplayed Alexander's womanizing, essentially describing it as his own business. He denied the defense's contention that Alexander was physically, sexually and emotionally abusive to Arias. And he hammered at the lies that Arias told, implying that if she told some whoppers early in the investigation to cover her guilt, then she was probably lying about everything.
"Every time she spat something out: another lie," he said.
He told the jury that he did not even want to discuss the lesser verdicts of manslaughter or second-degree murder. Instead he carefully laid out his theories of premeditation: How Arias had rented a car in California, brought gas cans, stolen a gun, dyed her hair, all to cover her tracks.
"Her plan was working well," he said. "She wanted to kill him and there was no one who would know she was ever in Arizona."
Martinez also painted Arias as a stalker and claimed that Alexander was afraid of her.
"There was no way to appease this woman who just wouldn't leave him alone," he said, pausing between words for dramatic emphasis.
And he displayed some of the more gruesome crime-scene photos, showing that Alexander's neck was gashed so deeply that his head was cut nearly halfway off.
On Friday it was the defense's turn.
Where Martinez had been theatrical, Arias' lead attorney, Kirk Nurmi, was plodding and deliberate, but he focused on dissecting the logic of Martinez's argument.
Arias claimed that Alexander was watching videos on his computer, sitting with his back to her when she first entered his house. If Arias had driven from California to Mesa just to kill Alexander, why didn't she do it then? Nurmi asked.
"You put the gun to his head and you do it!" he said. "You put the knife to his throat and you do it! What better time to do it?"
Why, instead, would she spend the night in his bed, make love to him, allow him to take naked photographs of her if she wanted to kill him and she didn't want anyone to know she was in Arizona? Why wouldn't she have killed him in the shower when he faced away from her, something memorialized in a photograph she took of him in the minutes before he was killed.
Martinez had presented as evidence of premeditation the fact that a gun of the same caliber that killed Alexander was stolen from Arias' grandfather shortly before the murder. Nurmi asked why Martinez insisted Arias brought a gun to kill Alexander and then stabbed him to death instead in a manner that would have required her to bend over awkwardly and stab Alexander with a back hand.
Nurmi played countless snippets of a recorded phone sex call between Arias and Alexander in which Alexander talked about 12-year-old girls having orgasms and the sex acts he wanted to perform and photograph with Arias, using porn-film terminology for many of them.
Then he moved on to Martinez's allegation that Arias was a stalker and that Alexander was afraid of her.
"Why do you take a picture of your stalker naked on your bed?" Nurmi asked, showing some of the photos that were taken on the day Alexander died.
Nurmi said Arias may have "snapped," and he told the jury that at most, the murder was a case of manslaughter, "sudden quarrel or heat of passion resulting from adequate provocation by the victim," he read from the juror instructions. "Sounds familiar."
The jurors went back to the jury room to select a foreperson. They told Judge Sherry Stephens that they would deliberate from 9 a.m. to 4 p.m., starting Monday. How long they take to reach a verdict - or an impasse - remains to be seen.