It was a dispute about having friends over and smoking marijuana that made Kevin Havelow angry with his mother, police say. After an early-morning attack Tuesday that left his grandmother dead, Havelow was arrested on charges of murder and attempted rape, the Chester County District Attorney's Office said Wednesday. The 23-year-old Chester County man - who just last month had spent a week in the hospital because he had expressed a desire to harm himself - threw his mother to the floor and attempted to rape her, according to police. As his sister called 911, his mother fought him off. Havelow went downstairs in their Lower Oxford home, police said, and pushed his 81-year-old grandmother onto her bed. He attempted to rape her, and digitally penetrated her as he had his mother, according to the criminal complaint. When his mother hit him with a broom to try to stop him, he threw her to the kitchen floor and began assaulting her again, police said. She escaped and locked herself in a room with Harvelow's sister, still on the phone with 911. Harvelow then retrieved knives from the kitchen and allegedly stabbed his grandmother, Aleen Watters, more than 20 times. He later described his two-handed stabbings to police as similar to actions in the video game "Donkey Kong."