Dennis Quinn appears in episode 381 as a nerdy and insecure friend of Marty Jackson who introduces him to his mother Meg Morris. Soon afterwards she starts getting mysterious phone calls by a threatening person. They get so bad that she soon involves the police and they place her under protection. In the end it turns out to be Quinn who has called and also murdered at least two other people (a prostitute and a policeman). He attacks Meg at home under knife-point. She is rescued by the police and Dennis is arrested.