Today, if you knew the name of a murderer - especially a cop killer, you can go through computers to find out, quickly, vital information and track down where the killer lives. However, 50 years ago, in a city of four million and no witnesses to a shooting, even if the cops knew his name it wasn't easy to find him (at least according to this episode of M Squad.)
In the opening scene, the killer's car conks out in a residential neighborhood. A cop comes by to help him, trying to figure out what's wrong with the car. After a few minutes, the driver pulls out a gun, shoots the cop and then takes the latter's car and escapes. Then he dumps the cop's car. Now where did he go? From the killer's past, M Squad knows the man has a history of killing, likes small blonds and says the phrase, "you bet" at lot. Our hero, "Lt. Frank Ballinger," gets another tip when it appears to killer ripped off a rare magazine. Frank thinks if the cops can find that magazine after it's been discarded, it could lead them to where the man is staying.
From that point on, this episode gives you a good look at how meticulous cops have to be at times with a lot of tedious work in finding a wanted man. Most detective work is dull, tedious labor but if often pays off. The boss in here, "Captain Grey" (Paul Newlan) is not convinced Frank's ideas are good in this case but he trusts him enough to let him try.
How it all plays out is pretty interesting. Lee Farr is good as killer "Rex Lang" and Russ Conway is solid as Frank's partner in this one, "Det. Ben Cooper. Conway, who just died about a year ago, was one of these no-name actors whose face you'll recognize from a ton of televisions shows from the '50s to the '70s. He guest-starred in many well-known TV programs and had a solid career in acting after moving to California as a young man from Canada.