Authorities in north-central Iowa’s Hardin County say a man shot and killed his son Monday after an argument turned violent. The shooting was reported just before 10 a.m. at a residence in rural Gifford, located five miles south of Eldora.

Hardin County Sheriff Timothy Smith says Larry Tremmel, 64, called 911 to report he shot his son, 31-year-old Josh Tremmel, who later died at a hospital. A neighbor said the two could be heard arguing in a car as they drove to the home, which they shared.

The elder Tremmel told investigators he was afraid his son was going kill him. Josh Tremmel was not armed. No charges have been filed in the case, which remains under investigation.