TODAY | March 01, 2013
>>> we're back now at 7:46 with a murder trial in phoenix that's trance fix iin transfixing the country. jodi arias is charged with murdering her ex-boyfriend.
>> did you kill travis alexander on june 4th , 2008 ?
>> yes, i did.
>> the simple answer is that he attacked me and i was defending myself.
>> but there aren't many simple answers here. jodi arias says she killed her boyfriend, travis alexander, because she feared for her life. the prosecution says it was a love story that ended in murder.
>> she rewarded that love by sticking a knife in his chest.
>> reporter: for two months a phoenix jury has heard the steamy details of their relationship. this tawdry tale is set against the backdrop of a religion. travis was mormon and had taken a vow of chastity.
>> jodi represent ed the decision of going after someone he was physically attracted to whereas some other girls represented settling down and having a nice, stereotipp stereotippical relationship.
>> reporter: they broke up and friends say jodi became confessed.
>> travis confided in us, she snoops through my e-mails, through my house. she checks up on me constantly.
>> reporter: when travis was found, stabbed and shot to death, his friends told police, look for jodi . she denied everything.
>> you're trying to cover it up, because that's you, all of you.
>> it looks like me.
>> reporter: police showed her explicit photos they found at the crime scene proving she was at his house, having sex . she changed her story, blaming intruders, then changed it again, saying travis attacked her. her credibility has been at the center of this trial.
>> you say you have memory problems but it depends on the circumstance, right?
>> that's right.
>> what factors influence your having a memory problem?
>> usually when men like you are screaming at me or grilling at me, or someone like travis doing the same.
>> reporter: soon it will be up to a jury to decide whether jodi is a murderer or a victim. for "today," josh mankiewicz , nbc news, phoenix.
>> you can see more of josh's reporting tonight on a special "dateline" at 8:00, 7:00 central time here on nbc.