Lou the Cop is one of Wiggum's two frequently used police officers.  Lou definitely seems to be the hardest working and most competent of the cops.

Lou Quotes

Chief Wiggum: Hold it right there, Switches of Eastwick.
Lou: Switches of Eastwick?
Chief Wiggum: I don't want to censor myself. That's how creativity dies.

Chief Wiggum: Who are you, the rules police?
Lou: No, we are the police police.

The Simpsons Quotes

Officer Eddie: (reading Steve Sax's license) Well well, Steve Sax, from New York City.
Officer Lou: I heard some guy got killed in New York City and they never solved the case. But you wouldn't know anything about that now, would you, Steve?
(Lou and Eddie laugh)
Steve Sax: But there are hundreds of unsolved murders in New York City.
Officer Lou: You don't know when to keep your mouth shut, do you, Saxxy Boy?

Wow, now I see why they call you Miss Hoover. You must have been vacuuming for an hour.

Bart