Stefan Chabrol is a murderer featured in Season 1. He is a commercial pilot from France who worked with his unnamed lover to murder his wife, Barbara, and dispose of her body at the airport in San Francisco. Adrian Monk caught wind of them when he noticed the height difference between Barbara and the imposter. During mid-flight he learned from an irate passenger that Adrian was onto him and needed to get him out of the way, then he had a chance encounter with Bernard, a fellow Frenchman associate, in which the fake Barbara exposed herself as an imposter. Stefan killed Bernard via poisoning. Upon landing in Newark, he and his lover boarded the plane for Paris until the plane was ground due to a false call from Monk, who gave Randy time to find the real Barbara Chabrol. He and his lover were then arrested for double homicide.