|Occupation||Lieutenant, later demoted to sergeant|
|Played By||Robin Weigert|
Davis is uptight, by-the-book and cares about enforcing the law, but nevertheless maintained a good friendship with Dani, regularly assisting Dani with her recovery program from addiction. With Crews, however, it was entirely opposite; Davis was distrustful of Crews and believed he didn't belong in the police force following his imprisonment. As a result, Davis regularly attempted to have Crews expelled from the department without success.
- In between Season 1 and Season 2, Davis, for reasons unknown, was demoted and returned to field work. Davis was originally a main character in Season 1. She made an appearance in the Season 2 episode "Not for Nothing".
- Karen Davis was played by Robin Weigert.