Nick Scanlon's car is a 1949 Chrysler Crown Imperial limo. In the crash scene, an older 1942 model was used. The 1949 side trim has been added, but the different front end reveals the switch.
An explosion at the home of Captain McQuigg rocked the interior of the home causing damage inside and throwing his wife, Mary, to the floor. When Captain McQuigg leaves his home there appears to be no damage to the front exterior of the home whatsoever.
When two hit men (Richard Reeves and Max Wagner) come to the home of Officer Johnson (William Talman) with the aim of killing him, Johnson gets the drop on them and shoots and kills both, in the presence of a newsman (Robert Hutton). Johnson then goes back to the police precinct house as if nothing happened and nothing is ever said about the shootings in the rest of the film.
Early in the film Officer Johnson recognizes one of Scanlon's henchmen, but later when Scanlon, a notorious mobster and "boss of the rackets", walks into the precinct Johnson doesn't know who he is. Dave Ames, a reporter, also doesn't know it's Scanlon when asked to identify him in connection with a crime he was a witness to.
At 0:20:00 in McQuigg's office, when Det. Sgt. Turk is asking about Officer Johnson the boom mic shadow moves over the framed photo of police officers on the wall behind Robert Mitchum.