This Officer Chen's worldview really is strictly black and white—only right and wrong—but he has no idea that the world is nowhere near as simple as he thinks.
Huo Sining did kill someone, but was that Fujiwara Seiho really innocent? A man like that, even dead, still deserves it a hundred times over. Yet relying on the laws of Huaxia Country, what can they actually do to him?
Unless extra-legal methods are used, otherwise as a Dongyang national, he's basically beyond the reach of Huaxia Country's laws.
What's more, there's a powerful force standing behind him; even if hard evidence of his murders were actually obtained, someone like that could still easily walk free. From that angle, Huo Sining's tactic of "killing with a borrowed knife" is actually the best solution.
