... says Inspector Carr (John Hamilton) to Dr. Crabtree (Donald Meeks).
In this short, two stock brokers and partners in a Wall Street concern are found shot dead early in the morning, in their offices, by a cleaning lady. Inspector Carr is called to the scene and he calls Dr. Crabtree, a criminologist and asks him to come and help out. They interview a stenographer found locked in the closet and two people swindled by the pair looking for the murderer.
Carr and Crabtree go at this mystery in a little bit different way than other installments of this series that I've seen. Carr is being the "bad cop" by yelling and accusing everyone, including an elevator operator who had no motive. Crabtree is the "good cop" - even though he is not actually a cop - talking respectfully to interviewees and trying to calm Carr down.
The solution to the mystery comes out of left field, and with both Carr and Crabtree seeming to know details they would not have had time to find out about, it is no wonder Carr is asking Crabtree "How the deuce do you know that???". Still the atmosphere and characterization of Carr and Crabtree are fun as always.