"She rewarded that love from Travis Alexander by sticking a knife in his chest," Martinez said in his opening statement. "And you know he was a good man, according to her. And with regard to being a good man, well, she slit his throat as a reward for being a good man. And in terms of these blessings, well, she knocked the blessings out of him by putting a bullet in his head."
But defense attorney Jennifer Willmott countered: "Jodi Arias killed Travis Alexander. There is no question about it. The million-dollar question is what would have forced her to do it?"
Willmott said Arias was the victim of a controlling, psychologically abusive relationship, and Alexander considered Arias "his dirty little secret."
Martinez accused Arias of playing the victim. He alleged she staged the crime scene to make it look like self-defense.
He also accused her of actively seeking to profit from her media attention.
Courtroom bomb threat
Earlier Thursday, the sheriff's office said a suspect had been detained after a reported bomb threat targeting the courtroom where the Arias trial is taking place.
Authorities found no evidence of explosives or threats at the courthouse, Sheriff Joe Arpaio told reporters. A search of the suspect's hotel room revealed bullets, but no gun or explosives, he said.
But Arpaio said deputies were interviewing the suspect and the investigation was ongoing.
"I hope this doesn't disrupt the trial. On the other hand, I think people have to know that this guy who made the threat is behind bars," he said. "Let's go on with the trial and see what happens."