A man who spent 41 years on death row in the US after being convicted of killing a woman has been released on bail after prosecutors said newly analysed DNA evidence did not link him to the crime.

Douglas Stewart Carter, who is now 71, was jailed for the killing of Eva Olesen in Utah in 1985.

He was sentenced to death but always maintained his innocence, stating that a signed confession was coerced.

The state Supreme Court ordered a new trial last year, citing misconduct by investigators, and a judge bailed Carter on Monday despite objections from the victim's family. He is required to wear a GPS monitor while on bail.

Olesen, the aunt of a local police chief, was stabbed multiple times and then shot in the back of her head at her home in Provo, Utah, in February 1985.

Carter, who is originally from Chicago, had been living with his mother in Utah at the time of the killing. Court documents show that police suspected him of killing Olesen during a robbery.

Believing he was a suspect in an unrelated case, Carter fled Utah but was eventually found in Nashville, Tennessee. He then signed a confession while under interrogation which he later said was coerced.

Despite there being no physical evidence linking Carter to the crime scene, he was convicted by a jury based on the confession and the testimony of two witnesses who said he had bragged about the murder.

But the witnesses later said in 2011 that they were told to lie in court, given cash and gifts by police and were threatened with deportation if they did not testify against Carter.

After more than a decade, the Utah Supreme Court last year ordered a new trial.

Lawyers representing Carter, who is black, said witnesses had seen a white man fleeing the scene of the murder and that an investigator had suppressed evidence pointing to the victim's husband, Orla Olesen.

They allege that prosecutors were close to filing charges against him, but a police officer asked them not to so he could continue investigating.

Olesen's husband, who died in 2009, told police he had found his wife dead in their home.

The victim's stab wounds were said to have been caused by a knife from their kitchen, which was discovered near her body. The gun was not found at the scene.

Then this month, prosecutors said that results of a DNA analysis excluded Carter as a possible match to blood found on a doorknob and genetic material recovered from the handle of the knife.

Carter's release comes against the wishes of Olesen's family.

Theresa Olesen, a daughter-in-law of Eva Olesen, said during Monday's bond hearing that her family had "serious concerns" about Carter's release. She said he should remain in jail while awaiting a new trial.

"By golly we were hoping for a concrete match," Olesen said of the DNA analysis. "It doesn't mean he wasn't there."

But Carter's defence attorney, Neal Hamilton, called for the case to be dismissed.

"If the state of Utah had their way, he would have been executed 15, 20 years ago before we discovered the misconduct," he told Associated Press.