Parents being charged for the child's actions

Ethan Crumley's parents have been charged and could serve 10 to 15 years in prisons because of their sons action where he shot and killed kids at school. Now I understand some of the reasons why they say that they should have known or seen some of the signs and that Ethan allegedly said that he was having trouble but to be charged for something that your child does anybody who has kids knows you don't know everything that your child is doing, kids do things without your knowledge but to hold the parents responsible for their child's action where they have to go to prison for 10 to 15 years.