After Mildred Kimber fires the gun, the vase on the table shatters. Within seconds the light bulb also appears to shatter and smoke. The next scene shows the light on and no longer smoking.
Dr. Rubin's phone number typed on the pill box is CR5I5I5. Several scenes later, when Perry starts to give Lieutenant Tragg the number, he starts with "Crestview 4..." before Tragg cuts him off.
After the fire is extinguished at Lola's apartment, the furniture shows no damage.
At 31:52 Tragg is racing to the Kimber apartment in a black 1957 Buick Roadmaster Riviera, but he arrives moments later in a black 1957 Buick Special. The cars have very similar lines but the Special has 3 "exhaust" ports and the Riviera has 4.
An unseen person starts an arson fire by splashing a flammable liquid on a pile of rags and tossing a lit match on them. The liquid is not really flammable; the rags catch fire immediately, but an adjoining puddle of the liquid does not.
In her living room, Mrs. Kimber is wiping off fingerprints from the revolver. Even though the gun goes off and destroys items on the pedestal table, nothing comes out of the end of the barrel.
A service revolver is stolen from a pocket of Bob Kimber's jacket and he supposedly fails to notice, but it's simply not believable that he wouldn't notice the theft of something that bulky and heavy.
Perry and Della are working late (it's dark out and the clock reads 11:55) when they receive a phone call from Lola. After a call to Tragg, they go to Lola's (Perry says it'll take a half hour to get there), where they spend a few minutes. Even though it must be long after midnight by now, Perry decides to pay unannounced visits to the homes of his client and then Sam Link, a nightclub owner he doesn't know. It's unlikely a lawyer would bother people at their homes so late.
In the lobby of Mildred Kimber's apartment building, Perry gives a "No comment" to a reporter's question and the reporters rush to get to a phone. One of the reporters walks between Perry and a photographer taking Perry's picture, which would ruin the shot, but the photographer turns and walks away without taking a second picture of Perry.