Go back to The Wire
Amy Ryan (Officer Beatrice "Beadie" Russell)
Russell is a cop without much real policing experience - as a port police she's spent most of her time directing traffic and checking shipping manifests. A single mother who isn't looking to complicate her life, it is Russell who discovers a container with its seal broken and finds the bodies of 13 women inside.
Although Russell is definitely out of her league with the murder investigation, she's the primary - until it is decided that Baltimore Homicide division will get the cases. She soon goes to work with Detectives Freamon and Moreland, who doubt her ability. She has questions of her own, but as the investigation progresses, she delivers key details that turn into leads for the case. Her knowledge of the docks, and her connections with the dockworkers - including Sobotka and Maui, an old flame - gets the detail access to the shipping tracking system. As she works the case, she learns that she has more interest and aptitude for police work than she ever imagined.
Another unexpected development from her work on the case was contact with Jimmy McNulty, who eventually found a quiet life with Russell tempting enough to lure him away from a life in the bars.