Responses
brutal satsujin
when the killer falls in love (it's shonen ai comedy but the MC is a killer and hides his identity w the world)
Ex police officer x burglar:
https://www.mangago.me/read-manga/on_doorstep/
Detective x thief:
https://www.mangago.me/read-manga/shiro_to_ao_to_yoru_to_asa_to_sorekara_no_detective_conan_dj/
Yakuza/mafia x detective/cop:
https://www.mangago.me/read-manga/omerta/
Also this:
https://www.mangago.me/read-manga/criminal_interview/
pls reccomend manwhas abt a detective/undercover and a like mass murderer person or someone who committed big crime (idk how to put it in english since its not my first language sorry)