Responses
Dealing drugs is in Japan a serious crimes. They are very severe about it. Plus the dude is the son of some rich dude. He mostly had more shady business going around. he was a yakuza after all. The cop seems to be more like a yakuza mole within the police, rather than a police officer being a mole in the yakuza world.

I doubt that guy with glasses is a cop—even if he’s undercover—he shot the Ikuya guy he was investigating in cold blood. That’s not normal, is it? They weren’t even dealing with an emergency, and I doubt that Ikuya guy was facing the death penalty because the worst he ever did was throw drug parties XD