Concept

Partner of Robbie Ritter, detective; ex-girfriend of Roland Ritter

Tropes

Detective in the Gang Crimes division
Sleeping with her partner, Robbie Ritter, who also happens to be the brother to her ex-boyfriend from high school.
Narratively, intended for her to discover Roland's secret, then start working with him to cover things up while (erroneously) believing that her partner (and lover) remains ignorant