Mickey Spillane's Mike Hammer - Season 1 Episode 29 Four Blind Mice

A man Mike helped get paroled from prison gets an anonymous letter accusing his wife of infidelity. Mike learns he's bought a gun illegally and tries to convince the ex-con's spouse to quit her glitzy job which requires her to be seen socially with a magazine editor known to have a roving eye before there's bloodshed. When the wife is found murdered and his friend's gone on the lam, Mike attempts to prove that the gun his friend bought was a different caliber than the one used to commit the crime.