S1·E20 Cinnamon Buns

Ann-Marie starts her first day as a detective and begins by organizing a raid on an apartment where an informant has told her two men are making bombs.

The precinct gets a new PAA, someone Phil remembers from his old precinct. He tells Santoro that she has a obsessive compulsive disorder that involves cleanliness and having to do everything four times. She is so annoying that she is always getting moved from station house to station house.