Please recommend some mystery mangas with no romance. Thank you.

How bout brutal seinin

Thank you but I've already read it.

http://www.mangago.zone/read-manga/mystery_to_iunakare/
http://www.mangago.zone/read-manga/funouhan/
http://www.mangago.zone/read-manga/juujika_no_rokunin/
http://www.mangago.zone/read-manga/ajin/
http://www.mangago.zone/read-manga/from_the_red_fog/
http://www.mangago.zone/read-manga/23_wards_tokyo_majo/
have you read?