This is one of my favorite episodes. Even though it's supposed to be serious the story comes off as unintentionally corny in parts, thanks to the way dead bodies are disposed of and a slightly over-the-top performance by former High Chapparal actor Henry Darrow. This is one of his first post-Chapparal roles, as a small-time mobster named Johnny. It would be his first of Darrow's 3 guest appearances on Hawaii Five-O, playing a different character each time.
Appearing as a hooker named Sally, Beth Brickell looks beautiful as always, but doesn't have as much to do in this episode as she would in her next appearance later in the same season with the lead guest role (as Carol) in "Good Night, Baby, Time to Die".
One of Johnny's men is Al Harrington in yet other villainous role (as Ray) before he replaced Kono on McGarrett's team as Ben Kokua starting in the 5th season. Harrington quit the show a couple of months into Season 7.
Another frequent guest actor in various small parts since this show began, Al Eben appears as Doc Bergman for the first time in this episode -- a part he would play for the remainder of the series.