Alternate episode title: The Lover.
The character of Roger Havilland, featured prominently in the television series, was actually killed off by author Ed McBain during one of the early 87th Precinct novels.
Jerry Paris had previously played Agent Martin Flaherty on The Untouchables and would go onto play Dr. Jerry Helper on The Dick Van Dyke Show.
Joan Staley was the 1958 Playboy Miss November.
Detective Havilland reveals in this episode that he was an All-American football player during his collegiate days.
Havilland: (to Cheryl): It's my job when there's been an explosion to ascertain if there's been a crime.
Cheryl: (to Havilland) As for wives, I don't play with married men. I don't have to.
Cheryl: (to Havilland) I won't be eating any home cooked meals for a while but with my cooking maybe that's a blessing.
Carella: (to Cheryl) A man offers you $100,000 and you don't even ask his name?
Cheryl: You must be tired.
Havilland: I'm used to it. We go around the clock about once a month.
Cheryl: Is it important for you to do something useful?
Havilland: Well, I think everybody's been put on earth to do their bit.
Kling: (to Cheryl) Just let me take you to the door. We don't have a chance to see many millionaires in our line of work.
Meyer: By the way, how's the victim?
Kling: Ask Havilland. He's taking her out tonight. A little dining and dancing.
Cheryl: You don't twist?
Havilland: Well, not while on duty.
Ruth: (to Havilland) Wipe the lipstick off. You're on duty.
Douglas: You're a suspicious little girl.
Cheryl: Let's just say that life has made me suspicious.
Warner: I deny everything and I demand to see my lawyer.