A reserve officer with the Piedmont (CA) Police Department reportedly shot his 21-year-old son to keep the young man from harming his wife in a violent attack.

According to the San Jose Mercury News, 52-year-old Todd Mather reportedly fired his handgun once after he heard his son physically attacking his wife.

The alleged assailant—who reportedly has psychiatric issues—had previously used a bludgeoning weapon to assault his parents and the father reportedly feared that he might use that weapon again.

After shooting him, the father administered first aid while waiting for EMS and police to arrive. The 21-year-old was transported to a hospital with non-life-threatening injuries and was later released.