PONTIAC, Mich. — Seeing her son in police custody just hours after he’d opened fire on his classmates at Oxford High School on Nov. 30, 2021, killing four and injuring seven, Jennifer Crumbley had a single question. “Why? Why?” she asked her son, Ethan, as he sat in an interview room in a substation of the Oakland County Sheriff’s Office in Oxford. Jennifer Crumbley is being tried on four counts of involuntary manslaughter for the deaths of the four students. Her trial marks the first time a parent has been charged with manslaughter in connection with a mass shooting. Her son pleaded guilty an…