Duncan is the sheriff of Cliffside, California.
During the events of Mortuary (1983) played by Bill Conklin
At the Sheriff's Department, Sheriff Duncan accuses Greg Stevens of stealing from Hank Andrews. Sheriff Duncan asks Greg where Josh is and Greg accuses Hank of having a seance, which he denies. Sheriff Duncan tosses Greg the keys to his van and tells him to leave. Later, Sheriff Duncan, Hank and Eve Parson have a meeting at the marina.