Confessions of a Dog (2006)

Takeda (Shun Sugata) is an honest police officer, father and husband, but after he's promoted to detective he quickly becomes embroiled in dirty back room dealings, blackmail, and corruption that goes right to the top of the force. Meanwhile renegade investigator Kusama (Junichi Kawamoto) must decide whether he should shake the foundations of Japanese law enforcement with the information that has come into his possession about the police. What will happen if both these men listen to their consciences?