Confessions of a Dog (ポチの告白), Gen Takahashi, 2006

Takeda is an honest police officer, father, and husband, but after he’s promoted to detective he quickly becomes embroiled in dirty backroom dealings, blackmail, and corruption that goes right to the top of the force. Meanwhile, renegade investigator Kusama must decide whether he should shake the foundations of Japanese law enforcement with the information that has come into his possession about the police.