UPDATE: Billy Hawk is back in the Hamilton County Jail as he begins to move through the retrial process.

On May 1, Hawk was granted a new trial.

He heads back to court at the end of the month.

UPDATE: A new trial has been granted to William Hawk, and a Hamilton County Judge has overturned his conviction.

Hawk is accused of killing Johnny "Mack" Salyer back in 1981. Salyer's body was found in a barrel in Lake Chickamauga.

Hawk was convicted of murder in the first degree and sentenced to life in prison in 2016.

Hawk's attorney Melanie Bean says his trial was horribly misleading because an investigator lied.

"Mr. Hawk's wrongful conviction was based upon a fundamentally unfair trial. That included the testimony of a known liar,” Bean said.

Bean and her team claim this isn't the first time the investigator lied under oath.

In court documents, Bean argued that the investigator admitted to committing perjury in an unrelated case, making his testimony in Hawk's case unreliable.

"And that's what made the prosecution misconduct in this case so significant and that's why I think it was highlighted in the court's ruling,” Bean said.

But the investigator's testimony isn't the only reason a retrial has been granted.

"There's a catalyst of this wrongful conviction was not based upon one error, but a culmination of many significant errors. That was built upon misleading, prejudicial and false evidence that was used by the prosecution,” Bean said.

Bean understands Salyer's family is still searching for answers, but says the state's mistrial has put the wrong person in jail.

"Mr. Hawk did not commit this murder. And the state's attempt to manufacture a case against Mr. Hawk has unfortunately clouted and perhaps further limited the ability to identify the true responsible party,” Bean said.

Hawk's conviction was the first for the Hamilton County Cold Case Unit.

District Attorney Neal Pinkston's office said they have no comment at this time.

Hawk's next court hearing is set for May 16.

Hawk remains in prison.

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PREVIOUS STORY: A judge has granted a new trial for a 65-year-old Chattanooga man convicted of a 1981 cold-case murder nearly three years ago.

In an order Tuesday, Hamilton County Criminal Court Judge Don Poole rejected Bill Hawk's motion for acquittal but agreed to grant him a new trial.

In a memorandum, Judge Poole stated that the Court granted the new trial on the grounds that "the defendant [Bill Hawk] did not receive a fair trial is basically attributable to acts or omissions relating to [a witness]."

Hawk is due in court May 16, 2019.

The Chattanooga Times Free Press contributed to this story.