An inmate suspected in the death of an Arizona jail guard filed a complaint two months ago saying the guard had looked at him inappropriately, Maricopa County sheriff's officials said.
The details in the claim could reveal a motive in the Tuesday attack on officer Gene Lee, KTVK-TV reported Thursday.
Suspect Daniel Davitt, 59, said in his complaint filed in U.S. court in August that Lee had stared at him in a restroom.
The claim was filed after the allegation was investigated and deemed unsubstantiated.
Davitt is suspected of knocking Lee to the ground, leaving him comatose with a head injury, jail authorities said. Lee was pronounced dead Wednesday.
Inmates at the Lower Buckeye jail often file complaints about officers, Sheriff Paul Penzone said.
"There was nothing in the ranks that gave any indication that there was going to be some escalation of violence," Penzone said. "It's just unrealistic to think you can move your modest staffing around every time that an inmate chooses to have some type of bitterness toward a detention officer."
Davitt awaits trial on sex crime charges. He is representing himself in the case.
Lee had a career as an engineer before signing up with the county, Penzone said.
"He volunteered in the organization for years then walked away from his job as an engineer at a stage in his life when many of us are looking to slow down or take in easy," Penzone said.