Class of 1984/WMG

Stegman's father is mentioned as being dead. What if Stegman killed him?
Peter Stegman hates having his perceived authority challenged. His father could have forbade him from doing something he wanted to do when he was younger, which would have angered Stegman. Mrs. Stegman is shown to be oblivious to her son's true nature, so Stegman could have offed his father and made it look like an accident.