Double Cheat: Itsuwari no Keikan

Takara Keisuke was a detective who chased after a major scammer. Now, he works as a police officer at a police box located along a shopping street. He appears like an ordinary police officer who is friendly with the people in the neighborhood, but Keisuke Takara has a hidden side. He is also Scammer K who targets bad people that are able to avoid the law.
(source : mydramalist)