The episode is called Painted Ladies. We used song titles for episode titles and as this one is about cops running an escort service it was either Painted Ladies or Roxanne and I like the shout out to Ian Thomas.
CTV describe the episode as:
Answering a call for "officer down," Frank (Aaron Douglas) discovers the victim is not a cop but a prostitute dressed as a cop. Investigating further, Frank uncovers an escort ring run by a ruthless vice cop.
Like many storylines on The Bridge, this one was inspired by events in Toronto.
There's more info on the true story here.