Kam Fong, who played Chin Ho, was a real Honolulu police officer for 17 years before changing careers to become an actor. He originally auditioned for the part of villain Wo Fat.

Danno was played by Tim O'Kelley in the 5-0 pilot. But a NY test audience told CBS they didn't buy him as a serious cop because he was too much of a "smart-cracking, Jimmy-Olsen-type gee-whiz kid." Leonard Freeman took the criticism to heart, and recast the part with James MacArthur for the series.

Actor Robert Brown (Jason of Here Come the Brides and Lazarus in the ST:TOS episode "The Alternative Factor") was originally slated to play McGarrett. A week before filming was to begin on the pilot, CBS asked producer Leonard Freeman to change the lead, giving no explanation. Freeman had to scramble for another leading man, and asked Jack Lord, whom he'd worked with on a previous (failed) pilot. Lord moved to Hawaii on a week's notice, and remained there throughout the series' run and for the rest of his life.

For years, much of the world was convinced that Five-0 was a real police unit. The studio once received a telex from a foreign government requesting assistance in locating a fugitive believed to be in Honolulu. Producers had to respond with the apology, "We're sorry, but Five-0 is just a television show."

Sunburned actors were a frequent problem for Hawaii Five-0's make-up crew. So many guest stars arrived in Hawaii early and sunbathed before reporting to work, the make-up team had to devise a special formula to neutralize red skin for the camera. Dubbed "mellow yellow," it remained a Five-0 make-up staple for all 12 seasons.

Though he somehow remained in office for all 12 years of Hawaii Five-0's run, the Governor never had a name until episode 208, when he was referred to as "Governor Paul Jameson." Most TV trivia sources wrongly insist that his name is Philip Grey - but this was another character played by the same actor (Richard Denning) in episode 6, "The 24-Karat Kill," before he was permanently cast as the Governor.

Throughout the first two seasons, both McGarrett and Danno often referred to "Chief Dann of HPD." This was a thank-you to CBS programming chief Mike Dann, who helped first persuade the network to put Hawaii Five-0 on the air, and also got it a better time slot later on.

McGarrett's address is said, in this episode, to be "404 Piikoi Street." This was in reality the street address for Hawaii Five-O's production offices.

This story was shot on location inside Oahu Prison, a dilapidated facility built in 1918 but still in use. Activists lobbying for prison reforms used footage from this episode to illustrate the need for long-overdue building upgrades.

Colonel Tyler receives an emergency call from "General Freeman." This was an in-joke homage to Five-0 creator and executive producer Leonard Freeman.

Hawaii Five-0's first season interiors were shot in a WWII-era Navy warehouse above Pearl City. The creaky building was infested with both rats and mongooses that were so noisy, one director routinely fired a starter pistol at the ceiling to scare them away before filming. Lacking air conditioning, the makeshift soundstage also reached over 120 degrees F when the studio lights were turned on. Fortunately, CBS increased the budget enough for producers to build a new, air-conditioned soundstage for succeeding seasons.

Five-0's film crew once helped the real HPD with a real-life arrest. Ten genuine cops, working crowd control during the filming of an episode, took a break from their guard duties and went into a nearby warehouse. They emerged with several gambling-ring suspects in handcuffs. The police lieutenant explained to the bewildered film crew, "Until today, we couldn't get near this place without tipping these guys off. Thanks for the great front!" The crooks had assumed that all the cops were actors, so hadn't given them a second thought.

Theresa's letter from Immigration is signed by "James Heinz," an in-joke. Heinz, in real life, was Hawaii Five-0's associate producer.

CBS had to reschedule this episode twice after pre-emptions for speeches by President Nixon. When Secretary of State Henry Kissinger visited Hawaii and asked to tour the Five-O studio, producer Leonard Freeman asked him for a favor in return. Could he talk to the president about that speech schedule? Within a week, Nixon's speeches were moved to a different night.

Roger C. Carmel, best known as Star Trek's Harry Mudd, played KGB agent Misha Toptegan in this episode. But his end credit lists the character as "Misha the Bear." This was a joking reference to Carmel's years as the voice of Smokey the Bear in hundreds of public service announcements throughout the 1960s.

Much of the art hanging in the upper levels of the gallery in this episode was painted by series star Jack Lord.