The officer is identified as Patrick Zeamer, a seven-year veteran of the St. Joseph Police Department.
Police say Zeamer shot and killed John Weipert, 47, during a domestic disturbance call at a home on the 1500 block of S. 41st Street Monday evening.
Investigators say Weipert was intoxicated and armed with a gun and threatening suicide.
A St. Joseph police negotiator tried to get Weipert to surrender but police say Weipert refused to comply.
Shots were fired after police say threatening acts were made toward officers on the scene.
Weipert later died from his injuries.
Zeamer has been placed on paid administrative leave while the shooting is under investigation.