At the end of the film when crime boss Arnie Valent is shot down on the street by police (and coincidentally, of all places, outside the very tenement building where his mother still resides), despite the fact her apartment is a couple of floors above street level, she throws open her window and immediately recognizes her son as the person shot. The director should have made her pause a little longer instead of reacting so quickly.
Because on several occasions during the film, crime boss Arnie Valent brazenly and openly admitted his criminal culpability to undercover accountant Barry Amsterdam, the latter could have obtained the necessary incriminating evidence against Valent and his accomplices if the authorities have had Amsterdam wear a wire (a covert listening device). Such technological innovations were beginning to be incorporated into crime solving during the 1950s.