MORGANTOWN, W.Va. -- A judge has postponed the civil rights trial of a West Virginia sheriff accused of beating a bank robbery suspect, giving his defense lawyers time to survey potential jurors and decide whether pre-trial publicity justifies a change-of-venue request.

U.S. District Judge John Preston Bailey ruled Tuesday that Jefferson County Sheriff Robert Shirley's lawyers had good cause to request the delay. The trial had been set to begin Jan. 22 in Martinsburg.

The motion came after prosecutors filed public documents with proposed evidence that they said shows Shirley had abused his power before -- and gotten away with it.

The filing included a transcript of testimony Shirley gave during a 2004 sentencing hearing in an unrelated case. In it, he admitted firing a gun while on duty during a personal dispute with another man.

That transcript, which shows the shooting never resulted in criminal charges or prosecution, "is evidence of defendant's readiness to abuse the power of his position," Assistant U.S. Attorney Paul Camilletti wrote in a notice filed with the court last week.

But Shirley's attorney, Kevin Mills, called the public revelation of a decades-old incident "highly inflammatory and presumably inadmissible." Besides ignoring Shirley's "long history of dedicated community service," he argued, the government's filing and media coverage about it could compromise his client's right to a fair trial.

Shirley has repeatedly denied any wrongdoing and vowed he will be vindicated.

"The result of this public filing is a poisoning of the pool of potential jurors right before the jury is slated to be picked," his lawyer wrote. He added that witnesses would now have to be re-interviewed.

"There are a myriad of prejudicial effects flowing from the government waiting until the eve of trial to dump all this information into the local and national presses," Mills argued.

Prosecutors could have opted for a closed filing, Mills said, to let the court rule on admissibility of the evidence "but for reasons unknown to the defense, they chose not to."

Shirley is accused of kicking and stomping Mark Daniel Haines after a December 2010 police chase and falsifying records during a subsequent investigation.

Haines is serving a 19-year sentence for bank robbery. Court documents say he suffered scrapes and bruises on his face and back during the beating, as well as a hemorrhage in his right eye, and a broken nose, rib and eye socket.

A separate civil lawsuit stemming from the alleged assault is scheduled for trial this fall.

Prosecutors in the criminal case also said they planned to introduce two video recordings from May 30, 2012, that show Shirley and another uniformed officer in what appears to be a booking room. The nature of the discussion on one video was not revealed, but prosecutors said the other had no audio.

The transcript, meanwhile, was from a sentencing hearing that former U.S. District Judge Craig Broadwater was holding in a separate case.

Shirley, then a lieutenant with 23 years of service, was testifying for the prosecution when he was questioned about his dealings with a man named Scott Rind over a piece of furniture that Rind had allegedly refinished and sold, knowing it belonged to Shirley.

Shirley testified that his wife, Debbie, had cheated on him with Rind years earlier.

"I was working one day, and I drove up on them and caught them in the act," he testified. "I shot at him one time, and that was it."

An attorney then asked if he typically shoots people who are sleeping with his wife while he's on duty.

"Well, I had never been faced with that before, but I did that time," Shirley responded. "I don't typically, no."

Shirley and his wife later divorced.