A Vernal police sergeant allegedly used a gun to assault a man last year after one of his officers was shot while responding to a domestic dispute on Halloween.

David K. Harris was served a summons Thursday to appear in 8th District Court in Vernal on one count of assault, a third-degree felony.

Harris, 48, was the sergeant on duty Oct. 31 when he and other officers responded to a shooting involving Vernal police Officer Dustin Gray.

Gray had responded to a report of a man hiding in some bushes outside a home. When Gray arrived he spotted 24-year-old Jesus Martinez peering into windows at the home of his ex-girlfriend's new boyfriend.

Gray was about 12 feet away when Martinez jumped out from behind a Dodge Durango, police said. Martinez allegedly fired four shots at Gray with a .40-caliber handgun, hitting him in the leg. The gunshot went through Gray's thigh without hitting any major arteries or bones, police said.

Martinez then shot into the residence, broke into the home and attacked the boyfriend. He pointed the gun at him and threatened to kill him.

After officers had arrived and arrested Martinez, Harris allegedly assaulted him and used his gun to do so, said Scott Reed, the chief of the Utah Attorney General's Office criminal justice division.

Reed declined to release details of the alleged assault but said he didn't think Martinez was hospitalized as a result of the confrontation with Harris. Reed said he didn't think the assault added up to a "prolonged encounter."

Harris is no longer employed by the Vernal Police Department, Reed said.

Prosecutors later charged Martinez with two counts of attempted aggravated murder and aggravated burglary -- first-degree felonies -- and four counts of aggravated assault causing serious bodily injury to another . He also was charged with felony discharge of a firearm and domestic violence battery, all third-degree felonies.

To avoid a conflict of interest, the Uintah County Attorney's Office asked the Utah Attorney General's Office to conduct an investigation into whether any criminal conduct occurred involving police that night.

Reed would not say if Harris admitted to assaulting Martinez but said, "The charge [filed against Harris] is based on conduct between Martinez and Harris."

Harris is scheduled to make his first appearance in court on April 19. He has not been booked into jail.