Listed as "The Case of Frank Corry" (IMDB) or "Morality and the Shield" (TV.com)
Season 1 Episode 20 (Aired: February 6, 1960)
A robbery gone wrong ends in the death of a police officer. The culprits flee the scene, leaving an eye-witness behind.
Frank Corry (James Drury) is a young police officer studying to be a lawyer. Because he feels silly sitting in class with a gun strapped on, he usually leaves it at home. This defies standard procedure as he is required to carry it with him at all times. Upon coming home, he realizes the weapon has been fired in his absence. Doing the right thing, he turns himself in for his negligence. Ballistics match his gun to the bullets that killed another policeman. Corry swears he's innocent but circumstance shines a bad light on him.
Before he 'grew up' and became a responsible citizen, he ran with Nino's (Leonard Nimoy) gang. A fact known to everyone at the precinct. He's also pinching every penny, juggling a fiancee and his studies on a policeman's income. Last but not least, the night watchman identifies him as a possible suspect in the robbery turned homicide. The investigating police officer, Lt. Weston (John Doucette), is pretty certain Corry was involved after the line-up, even though the night watchman says he can't be a hundred percent sure. He was hit over the head when he disturbed the culprits and only got a fleeting glimpse of of the gang. Still, Weston keeps his promise to continue his efforts to look for evidence exonerating him as Corry insists on his innocence.
Not putting his trust solely in the police investigation, Corry's lawyer starts asking questions around Corry's neighborhood. He's observed by Nino and his brother who get nervous in the face of the attention put on people who know Corry and know his schedule. Nino decides to teach the lawyer a lesson. Maris (Macdonald Carey) is lured into a dark alley and ambushed by three thugs who tell him to stay away from their turf. He doesn't get a good look at their faces, but their boots he remembers well. Nino is his prime suspect for the beating and Corry confirms that while he was part of the gang those kind of boots were popular on the street but have since gone out of fashion with the younger crowd. More importantly, as Corry's friends, Nino, his brother and Johnny knew his daily routine. On a pretense Maris pays Nino a visit and accuses him of shooting the police officer. They feel fairly on top since three guys were involved and it's just he and his brother in the apartment - until the third member of their gang comes by. Nino draws a knife and suggest they take the lawyer to a nice and quite place. The police shows up just in time to safe his ass, in the course of which Nino's brother catches a bullet.