The trial of a man accused in what prosecutors characterized as a New Kensington revenge killing was postponed Monday because a key witness could not be located.

Jury selection for Larry Osborn Nix II, 47, of West Brownsville, Washington County, was scheduled to get underway in Westmoreland County court. Instead, the trial was delayed after prosecutors told a judge they have been unable to find the woman whose testimony is vital to establishing a motive in the death of James Michael Hayes, 31.

Hayes was found dead Dec. 9, 2022, with a gunshot wound to the head in the parking lot behind Kensington Arms Apartments in the 400 block of 11th Street. The fatal shooting was the first criminal prosecution to be recommended by a Westmoreland County grand jury that for 18 months heard evidence in unsolved cases. The grand jury has since wrapped up its work.

Prosecutors contend evidence presented to the grand jury linked Nix to Hayes’ murder. Witnesses said the shooting was the final act in a series of events that started with allegations Nix robbed a victim and then was shot at by Hayes in retaliation.

Assistant District Attorney Katie Ranker Ellwood emphasized the importance of the missing witness during a pretrial hearing last week. Ellwood said the woman’s testimony was a key aspect of the case because it linked Nix to a prior robbery and showed he was previously targeted in a shooting.

“It provides the motive for the homicide,” Ellwood said.

On Monday, as the trial was set to begin, Ellwood told Westmoreland County Common Pleas Court Judge Meagan Bilik-DeFazio that sheriff’s deputies have been unable to locate the woman who was expected to testify about the events that led up to Hayes’ killing.

The judge last week issued a material witness warrant to ensure she was present at the trial.

Bilik-DeFazio rescheduled the trial to begin in July as law enforcement continues to search for the witness.

Defense attorneys Brian Aston and Ned Nakles agreed to the one-month delay.

Since his arrest last year, Nix has pushed for a speedy trial as he maintains his innocence. He has denied any involvement in Hayes’ murder, and defense attorneys have previously argued that prosecutors cannot produce witnesses who can positively identify Nix as the man who fired the fatal shots.

Witnesses testified before the grand jury that a man who matched Nix’s description fired on Hayes after he stopped his vehicle to retrieve a jacket from its trunk.

Police said 41 rounds were fired from three guns, all from a distance from where Hayes’ body was found.