Scanlon first appears in a Season Two episode, Block Party, where he acts to deny credit to Detective Janice Wentworth (Linda Lavin) for stopping a murder from taking place. His attitude is decidedly sexist, and he already indicates the 12th is under his scrutiny, though largely to no avail.
He next shows up in Season Four's Chase, where he is revealed as the one who planted a phony drug pusher who offered each of them large bribes in exchange for letting him go. Once more, the squadroom's frustrations are met with Scanlon's own at not getting so much as a single officer to take the bait.
Scanlon makes two appearances in Season Five. In the first, Accusation, Scanlon is quick to move on a controversy surrounding Detective Arthur Dietrich, but is again frustrated when the accusations in question turn out to be the fantasy of a lonely admirer.
If the always-calm Dietrich somehow bore a grudge, he got Scanlon back in a big way during his next appearance in the episode, Voice Analyzer, where a scientist with an advanced lie detector is used to trip up the detectives with Scanlon using HUAC/McCarthyist tactics in his questioning, ones meant to increase frustration and almost guarantee a bad answer. When Dietrich's turn comes at the end, he gives answers claiming that he is an alien being of many centuries' longevity, among other impossibilities. Dietrich then claims that his deception is as simple as keeping his voice absolutely calm at all times; so that anyone who could do this could negate the value of the voice analyzer, while conversely, anyone easily frustrated (like Sergeant Wojohowiecz) was more likely to fail.
Scanlon again showed his blatant bigotry in the Season Six episode, Inquisition, actually costing the precinct a valued officer, after a fashion. Officer Zatelli, who had revealed to Barney and then the precinct in earlier episodes that he was secretly homosexual, was outed when Scanlon came in, pursuing an officer at the 12th that an anonymous letter had revealed to be gay, likely written by Zatelli himself, in frustration over NYPD policies on the matter. A full-court press with sanction from on-high had Scanlon's accusations wilder than ever, till a nervous Wojohowiecz gave up the secret. Once again, Scanlon's efforts met with frustration : Zatelli, implied to have in-closet friends in high places, left to take on a job in the NYPD with much more authority and higher pay.
While Scanlon appears in the two-part Season Six episode Dietrich's Arrest, he can do little more than gloat while quoting departmental rules against officers' political involvement, rules that Barney feels are likely unconstitutional. Dietrich, willingly arrested for taking part in an anti-nuclear protest, at no time disputes what he did, leaving Scanlon nothing to investigate.
Scanlon did not appear in the Season Seven episode, Field Associate, but his presence can be felt. Barney receives a report from Internal Affairs that in essence takes many of the characteristics and quirks of the detectives and uses them as a basis to chastise. While Dietrich's talking, Harris's very stylish dress code, and Wojo's chronic lateness don't have them up on charges, it does point to the presence of a mole in the precinct reporting all this to IA. That mole is revealed to be long-time character Officer Carl Levitt, who, besides resenting the hurtful talk about his small stature, was told by Internal Affairs that if he didn't do this, they would find someone else. By it being a friend, he was able to keep the information mild and even petty in nature. On the one hand, the tension and resentment this caused was well within Scanlon's MO; on the other, it was a bit more subtle than his in-your-face ventures. The series often used real NYPD officers as sources for material, and this showed the generally dim view of Internal Affairs many regular officers hold to. Perhaps if Scanlon were behind this, the officers shrugged it off, more upset with Levitt's out-of-character actions than Scanlon's trademarked ones.
The tables were turned and his Karma Houdini status upended on Scanlon during the show's eighth and final season.
In the episode Chinatown, Scanlon starts off by humiliating Wojohowiecz by getting him to openly admit his sterility, a recent and painful revelation for the now-Detective. However, when a beautiful and wealthy mugging victim rebuffs his interest in her, Scanlon finds himself the subject of harrassment charges. While almost a sympathetic moment as the viewer sees how very lonely the man is, his actions, past and present, negate this to a large degree. In addition, he once more resents the 12th's officers for having the decency not to gloat too much at his peril.
In the series final episode, Landmark, Scanlon arrives, sad in his own way at the 12th Precinct's closure, since it means he will never find that incident that mars its perfect record. After he snarks at the detectives about the various things he has investigated them for, he gives Barney a very grudging and perfunctory congratulations on his finally getting promoted to Deputy Inspector—something that Barney himself had yet to learn of. Scanlon shrivels and withdraws at the thought that he was the first one to tell them of Barney's triumph.
In the series First Season, a character named Kelly investigates the 12th in an episode called Graft. But while his bluster causes some frustration and worries for the 12th about minor things being made into big cases, he is self-defeating and is demoted when his crusade touches the wrong people. He seems to accept his downfall with more grace than Scanlon ever did, and could be seen as an early attempt at this type of character, lacking the gleeful sleaze that George Murdock (Died 2012) brought to the table.
While Scanlon never devolved into parody the way inquisitor characters like M*A*S*H's Colonel Flagg did, Barney Miller as a series remains unique for putting character first, even for a recurring nemesis like Scanlon.
- George Murdock had a long acting career, including two memorable Star Trek appearances. He was the false God that drew in Sybok in Star Trek V : The Final Frontier and the decidedly more heroic yet equally doomed Admiral J.P. Hanson in Star Trek : The Next Generation's memorable The Best Of Both Worlds, where his fleet was destroyed by a Borg incursion.