James Crumbley, 47, was charged with involuntary manslaughter after his son killed 4 boys at a Michigan school. His wife, Jennifer, will be sentenced next month, guilty of the same charges.

This case is believed to mark the first time that the parents of a mass shooter have been held criminally responsible. In the United States, pressure to punish parents is increasing given the number of gun deaths involving minors. The mother testified during her trial that she bought her son Ethan a 9mm SIG Sauer pistol as an early Christmas gift.