Return of the Bloodthirsty Police is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

After being betrayed and killed by the organization he worked at, the infamous assassin ‘Bi-Gwang’ reincarnates as ‘Kim Gyeongsoo’, a police officer. He vows to take revenge on ‘Hwaguksa’, the organization of killers that has betrayed him.