Kei X Yaku Bound By Law vol 2 back

Despite being on opposite sides of the law, Public Security Bureau agent Ichiro and yakuza lieutenant Shiro use a whirlwind romance as camouflage for investigating the mystery of Rion Nakaba's disappearance. While Shiro had already been looking into the politicians and criminals mentioned in the journal his sister left with him, not everything in her notes is as it seems. When the fake lovers catch a break in the case, they find themselves stepping into more dangerous waters than either could have anticipated.