PHELPS, Ky. (AP) — Authorities say a trooper in eastern Kentucky was investigating an assault complain when he shot and killed a man.

Kentucky State Trooper Steven Mounts tells news outlets that 32-year-old John Casey was killed Sunday morning in the Phelps community of Pike County after he assaulted a trooper, prompting the trooper to fire his weapon. Casey was pronounced dead at the scene.

Laura Casey, the man's sister, says her brother was unarmed and was not involved in an altercation with the trooper prior to being shot.

A trooper was taken to a nearby hospital with minor injuries.

Authorities have not released Casey's race or that of the unidentified trooper who shot him.

Casey's body was sent to Frankfort for an autopsy.