Jodi Arias Claims Travis Alexander Showed Increasingly Aggressive Behavior

Feb. 13, 2013— -- Jodi Arias' ex-boyfriend Travis Alexander became increasingly sexually aggressive and violent toward her in the weeks leading up to a confrontation in which she killed him, Arias testified today in her murder trial.

Arias read text messages aloud that Alexander had sent her calling her his "sex slave" and describing aggressive sexual fantasies he had. The pair were no longer dating, but continued to sleep together as they dated other people.

"You are the ultimate slut in bed," Alexander wrote in the messages. "When it's done, the intensity will make your body feel like you have been raped… You'll rejoice in being a whore that's sole purpose in life is to be mine, to have animalistic sex with me and to please me in any way I desire."

Arias also said that he forced her to end friendships with both male and female friends in late 2007, called her a "whore" for being friendly with other men, and began to lose his temper over the phone and in person during frequent arguments.

Arias said she grew tired of his "aggressive, authoritative" behavior and began to distance herself from him, moving away and then writing him a long email telling him that she was never comfortable with their relationship being a secret and that she wanted to "cool it" a little bit.

On the day she moved away from Mesa, Ariz., to California in March 2008, instead of waving good-bye Alexander gave her a rude gesture with both hands, she told the court today.

In the middle of May, 2008, Arias wrote Alexander an email from California saying that she was tired of him keeping their relationship and friendship a secret, and was going to distance herself from him.

"The entire extent of our association was a secret. I just tolerated it and tolerated it and tried not to let myself think about it," Arias said about her motivation for writing the letter. "I didn't want him to feel obligated to be my friend to spare my feelings."

She told Alexander she was going to "be proactive and remove (herself) from the list of people you have to worry about," but that she loved him and would always be his friend and confidante.

Alexander exploded when he received the email, Arias said today. He wrote angry instant messages to her by computer and cruel text messages after.

The testimony has followed four days of accusations that paint Alexander as increasingly abusive and sex-obsessed. Arias has claimed Alexander pushed her to the floor, kicked her in the ribs, and broke one of her fingers during an argument. In addition, she testified that Alexander told her that he was sexually attracted to young children and wanted to make a pornographic movie with her.

Catching Up on the Trial? Check Out ABC News' Jodi Arias Trial Coverage

Arias' defense attorneys hope the details of the couple's sex life will help convince the jury that Alexander became so threatening to Arias that she had to kill him in self-defense.

Though she has been on the stand for five days, Arias has not yet described what happened on June 4, 2008, when she stabbed, slashed, and shot Alexander in his bathroom after a day of having sex and taking nude photos.

Arias is charged with Alexander's murder and could face the death penalty if convicted.

Earlier in the day, the judge presiding over the homicide trial rejected Arias' plea to remove the possibility of the death penalty if she is convicted.

Judge Sherry Stephens made her ruling after defense attorney Kirk Nurmi argued for a mistrial as he and prosecutor Juan Martinez became increasingly tense with one another.

Nurmi said that Martinez had violated a court order by having potential witnesses who were watching the trial at home text him helpful information, including inconsistencies in testimony. A friend of Alexander's testified this morning that she had been in contact with Martinez's paralegal while watching the trial at home, contacting the paralegal whenever she had helpful information about testimony she heard.

He said that violated the judge's order that witnesses not watch trial.

"To impose no sanction is to condone the behavior, to say that there no consequences for that kind of behavior," Nurmi said, alleging that Martinez's misconduct had pervaded Arias' trial and made it impossible for her to receive a fair trial.