(CBS) - For more than two hours on July 15, 2008, Jodi Arias denied being anywhere near Travis Alexander's home on the night he was brutally murdered, telling the detective questioning her that if she had killed her ex-boyfriend she would "beg for the death penalty."
Arias is now on trial for first-degree murder in the June 2008 death of Alexander, who was found in his Mesa, Ariz., apartment with 27 stab wounds, a slit throat and a gunshot wound to the head. If convicted, she could indeed get the death penalty.
In 2008, Arias told that Alexander was killed during a home invasion. Today, she admits she killed Alexander, with whom she had an on-and-off sexual relationship, but says she did so in self-defense.
This nearly three-hour long video of her first interrogation clearly shows that Arias' story has evolved. When she was first arrested in Siskiyou County, Calif., Arias spent hours trying to convince a skeptical detective that she wasn't even in the same state as Alexander on the day he died.
"If I killed Travis I would beg for the death penalty," she says.
Under questioning by an Arizona detective, Arias claimed that she rented a car and got lost on a solo road trip in California. Her phone was off, she said, because she ran out of gas, misplaced her phone charger, and had to sleep in her car.
The detective lets her talk, giving her a piece of paper to show him her supposed route, but eventually tells her he simply doesn't believe her - and that he has proof she was in Alexander's home when he was brutally murdered. That proof, he tells her, includes her hair and blood mixed with Alexander's.
"There is no way anyone else could have left your palm print in blood on that wall," the detective tells her.
Arias says there must be some other explanation - she says she once cut herself while bathing Alexander's dog in the bathroom and the blood might have come from that.
"There is no reason I would ever want to hurt him," she says. And later: "If I was going to ever try to kill somebody I would use gloves. I've got plenty of them."
Over and over, the detective asks her to come clean: "Why won't you admit it?," he asks. "You were there. Quit playing this game."
But over and over, she denies being involved. "I've never been that angry at him," she says. "If I did that, I'd be fully ready to face the consequences...I'm all for the ten commandments - thou shalt not kill."
Near the end of the interrogation, the detective tells Arias that she'll be booked into the local jail within an hour or two and she says, tearfully: "This is a really shallow question and it's going to reveal how shallow I am. But before they book me can I clean myself up a little bit?"
The detective says no, and soon after he leaves her alone in the interview room, she says to herself, "You should have at least done your make-up Jodi, gosh."
As she waits to be booked, Arias looks through the trash can, does a headstand against the wall, and quietly sings, "O Holy Night."