(Reuters) - A jury in Arizona failed to reach a verdict on Thursday in the sentencing retrial of Jodi Arias, sparing the former waitress from the death penalty for murdering her ex-boyfriend in 2008.

Arias, 34, was found guilty of the murder in 2013 but jurors at that trial deadlocked on whether to give her the death penalty. A new jury of eight women and four men was seated in October to hear a sentencing retrial but announced on Thursday it could not decide on a punishment.

Maricopa County Superior Court Judge Sherry Stephens said the jury was hung and declared a mistrial. The judge now will sentence Arias to life in prison or to life in prison with the possibility of parole after 25 years.

Both sides will have an opportunity to make their case to the judge before she makes that decision.

Prosecutors accuse Arias of murdering her ex-partner, Travis Alexander, in a jealous rage but she says she acted in self-defense. Alexander, 30, was found dead in a shower at his Phoenix-area home. He had been stabbed multiple times, his throat was cut almost from ear to ear, and he had been shot in the face.

(Reporting by David Schwartz; Writing by Daniel Wallis; Editing by Cynthia Johnston, Paul Simao and Bill Trott)