The title of this great little film is a direct quote from
Casablanca.
In Casablanca, in the early part of the film, the local police inspector is talking to his officers about how to begin an investigation of a murder. When someone quizzes him on where to start, he waves his hand in a dismissive manner and says:
"Round up the usual suspects!"
The quote is used again, later in the film.
This phrase is now often used to describe behavior of corrupt bureaucracies.