Exact Words: The wife of the victim in the opening scene is suspicious when he returns home with some expensive purchase and asks if he's been gambling again. He gives her his oath that his purchases weren't made with gambling winnings. They were from the money in a wallet he found, the rest of which he did gamble with.
Logic Bomb: How George brings in the killer. He explains to Mrs. Lind he didn't take the wallet for himself, but to catch a criminal. Her draconian sense of morality accepts this as justified, so she hands over her gun.
Misplaced Retribution: Mrs. Lind's murderous outrage is for her philandering husband, but he's already dead, so she needs to find others of dubious character to take it out on.
Secret Test of Character: The killer leaves a wallet with an address and 10 dollars on a corner, observing who picks it up as a morality test, murdering those who fail by pocketing the money rather than returning it to its apparent owner.
