Tom Hardy (Willis) is a 5th generation Pittsburgh cop investigating a serial killer, the Polish Hill Strangler, when he is demoted to river patrol for suggesting that the serial killer is another cop.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...