These convictions confirm repeated acts, or lack of acts, that could have halted an oncoming runaway train.

Ethan previouslypleaded guiltyto all of the charges against him, including murder and terrorism.

He wassentenced to life in prisonwithout parole in December 2023.

PONTIAC, MICHIGAN - APRIL 9: Jennifer Crumbley looks at her husband James Crumbley during their sentencing on four counts of involuntary manslaughter for the deaths of four Oxford High School students by their son, mass school shooter Ethan Crumbley, on April 9, 2024 at Oakland County Circuit Court in Pontiac, Michigan. The Crumbleys are the first parents in U.S. history to be criminally tried and convicted for a mass school shooting that was committed by their child. ((Photo by Bill Pugliano/Getty Images)

Jennifer Crumbley looks at her husband James during their sentencing on four counts of involuntary manslaughter for the deaths of four Oxford High School students by their son on April 9, 2024 in Pontiac, MichiganBill Pugliano/Getty Images