The trial of a man accused of raping, murdering and eating parts of his ex-girlfriend's body has ended in a mistrial.

Joseph Oberhansley, 38, is facing life in prison without parole on charges of murder, rape and burglary after prosecutors say he stalked, raped, and killed 46-year-old Tammy Jo Blanton before eating parts of her body in 2014.

His trial began Wednesday in Jeffersonville, Indiana, in Clark County Circuit Court, but was quickly cut short after a state’s witness mentioned his criminal past and previous drug use.

The witness was a close friend of Ms Blanton. She said during the trial in that her friend didn’t called the police following an incident between her and Oberhansley because she “didn’t want him to go back to prison.” She also mentioned a conversation she had with her friend about the influence of drug use on Oberhansley’s behaviour.

"This puts him in great peril," Clark County circuit judge Vicki Carmichael said in open court Thursday. "A simple admonishment to disregard [the comments] would be insufficient and certainly would not clear the prejudices created by the witness' testimony.”

US Navy SEAL on trial accused of murdering wounded Isis fighter Show all 11 1 /11 US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher leaves court with his wife Andrea 17 June 2019. He is on military trial at San Diego Naval Based accused of murdering a wounded Isis fighter in Iraq in 2017. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher leaves court with his wife Andrea 18 June 2019. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE HANDOUT Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter US Navy SEAL Special Operations Chief Edward Gallagher poses with his wife Andrea. Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE HANDOUT Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter This undated selfie provided by Andrea Gallagher shows her husband, U.S. Navy SEAL Edward Gallagher, who has been charged with allegedly killing an Islamic State prisoner in his care and attempted murder for the shootings of two Iraq civilians in 2017. Gallagher is scheduled to go on trial Monday, June 17, 2019. (Edward Gallagher/Courtesy of Andrea Gallagher via AP, File) Edward Gallagher Andrea Gallagher via AP US Navy SEAL on trial accused of murdering wounded Isis fighter Former US Army member King Cohn arrives at court to support US Navy SEAL Special Operations Chief Edward Gallagher during the first day of jury selection on 17 June 2019. REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter Former U.S. army member King Cohn arrives at court to support U.S. Navy SEAL Special Operations Chief Edward Gallagher during the first day of jury selection at the court-martial trial at Naval Base San Diego in San Diego, California , U.S., June 17, 2019. REUTERS/Mike Blake MIKE BLAKE REUTERS/Mike Blake US Navy SEAL on trial accused of murdering wounded Isis fighter FILE PHOTO: U.S. Navy SEAL Special Operations Chief Edward Gallagher, charged with war crimes in Iraq, is shown in this undated photo provided May 24, 2019. Courtesy Andrea Gallagher/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES, NO ARCHIVE/File Photo Handout . Andrea Gallagher via REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter Defence attorney Timothy Parlatore, representing US Navy SEAL Special Operations Chief Edward Gallagher, speaks with reporters at a pre-trial hearing. Earnie Grafton/REUTERS US Navy SEAL on trial accused of murdering wounded Isis fighter FILE - This 2018 file photo provided by Andrea Gallagher shows her husband, Navy SEAL Edward Gallagher, who has been charged with murder in the 2017 death of an Iraqi war prisoner. Lawyers for Gallagher are seeking to have the charges dismissed for alleged prosecutorial misconduct. Attorneys for Special Operations Chief Gallagher are scheduled to argue in military court Wednesday, May 29, 2019, that the case against him has been tainted by lies, withholding evidence and conducting surveillance on the defense. (Andrea Gallagher via AP, File) Andrea Gallagher Andrea Gallagher via AP

The prosecution agreed. The trial will likely resume in September, with a jury pulled from the same pool.

Clark County prosecutor Jeremy Mull told jurors on Wednesday that "Joseph Oberhansley butchered Tammy Blanton like you wouldn’t kill a livestock animal."

Mr Mull told the court that Oberhansley killed Ms Blanton at her home, forcing down the door to her bathroom, where she had been hiding to try to save her life.

In a videotaped interview with the police, Oberhansley described the murder in chilling terms, saying "Truth be told, she really wasn't all that scared, surprisingly. Like she knew [she was going to die], you know what I mean?"

“In her last moments,” Mr Mull told jurors, “she wasn’t going to give him the pleasure of seeing her scared.”

Oberhansley’s mental competence has already delayed the trial by several years. In the now cancelled trial, prosecutors agreed not to pursue the death penalty in exchange for the defendant promising to not use insanity as a defence.

But Oberhansley's attorney Bart Betteau told jurors on Wednesday that he hoped they’d “keep an open mind” regarding his client’s state of mind.

"Her chest had been cut open. The heart was removed. The heart was eaten," Mr Betteau said. "I'm sorry that I have to go over this, but that's what the evidence is. Think about the process and say to yourself, is this someone who’s thinking right?”

In 2000, Oberhansley was sentenced to 12 years in the Utah State Prison for manslaughter after he shot and killed the mother of his child in a "meth rage," according to court records. He also shot his mother, shot at his sister and infant son, and then shot himself in the head and survived.