Mona Cameron (Cara Williams) is the main villainess from Alfred Hitchcock Presents episode 1.37, "Decoy" (airdate June 10, 1956).
Mona Cameron is a singer and the wife of producer Ben Cameron, and in the beginning of the episode, she is shown practicing with Gil Larkin, who is secretly in love with Mona. After Gil notices a bruise on Mona's arm, Mona stated that Ben gave it to her, claiming that he abuses her. An angry Gil headed to Ben's office to confront him, only to be knocked out from behind by an assailiant named Ritchie, who later shoots and kills Ben.
It was later revealed that Mona was the mastermind behind her husband's murder, with the reveal coming after Gil (who returned to Mona's home after being interrogated by police) heard a familar musical tone playing; the same song that played when Ben was on the phone. Not only was Mona the one who phoned Ben, but she sent Ritchie to kill Ben and set up Gil for the murder. At that moment, the evil Mona called for Ritchie, who had a gun pointed at Gil, and planned to kill Gil and make it look like he committed suicide due to guilt over killing Ben. The police crashed into the home and arrested Ritchie, and did the same to Mona after she tried to convince them that she was the victim. Ironically, Mona's last words before her arrest had her telling the police to be careful because she "bruises easily."
- Cara Williams later appeared in Season Five's "The Cure" as the evil Marie Jensen.