PONTIAC, Michigan (AP) — The parents of a teen accused of killing four students at a Michigan high school were charged with involuntary manslaughter Friday as a prosecutor described chilling moments that day when a teacher found a drawing of a gun, a person bleeding and the words “help me” at the boy’s desk.

Oakland County prosecutor Karen McDonald said the parents committed “egregious” acts, including buying a gun and making it available to Ethan Crumbley and failing to intervene when they were summoned to the school Tuesday and confronted with the drawing.

School officials told James and Jennifer Crumbley to get their 15-year-old into counselling, McDonald said. He returned to class and later emerged from a bathroom with a gun, firing at students in the hallway, according to police.

“These charges are intended to hold the individuals who contributed to this tragedy accountable and also send the message that gun owners have a responsibility,” McDonald said. “When they fail to uphold that responsibility, there are serious and criminal consequences.”

Jennifer Crumbley texted her son after the shooting, saying, “Ethan, don’t do it,” McDonald said.

It wasn’t immediately known if the Crumbleys have lawyers who could comment on the involuntary manslaughter charges. Under Michigan law, the charge can be pursued if prosecutors believe someone contributed to a situation where harm or death was high.

Parents in the US are rarely charged in school shootings involving their children, even as most minors get guns from a parent or relative’s house, according to experts.

Sheriff Mike Bouchard disclosed Wednesday that the parents met with school officials about their son’s classroom behavior, just a few hours before the shooting.

The superintendent for the district late Thursday posted a YouTube video where he said the teenager was called to the office before the shooting but “no discipline was warranted.”

Ethan Crumbley has been charged as an adult with two dozen crimes, including murder, attempted murder and terrorism, for the shooting Tuesday at the Oakland County school, roughly 30 miles (50 kilometers) north of Detroit.

Four students were killed and seven more people were injured. Three were in hospitals in stable condition.