The judge in a murder trial that riveted Americans with its details of sex and violence has declared a mistrial in the life-or-death penalty phase after the jury said it could not reach a decision.
Travis Alexander was stabbed and slashed nearly 30 times and nearly decapitated at his home. The jury determined the killing was cruel enough to merit consideration of the death penalty.
Arias' trial was streamed live on the internet and became a real-life soap opera to people around the world.
If a new jury cannot reach a unanimous decision, the judge would sentence Arias to spend her entire life in prison or to be eligible for release after 25 years. The judge cannot sentence her to death.
The verdict came two days after Arias spoke directly to jurors and pleaded for her life. She said she "lacked perspective" when she told a local reporter after her conviction that she preferred execution to spending the rest of her days in jail.
Arias, 32, says she killed Mr Alexander in self-defence when he became enraged after a day of sex, forcing her to fight for her life. Prosecutors say she attacked him in a jealous rage because he wanted to end their relationship and go to Mexico with another woman.
Her case became a sensation from the beginning as Arias gave a series of jail interviews following her arrest in which she blamed the killing on armed, masked intruders.
The case provided endless amounts of cable TV and tabloid material, including a recorded phone sex call between Arias and the victim, nude photos and bloody crime-scene pictures.