can anyone please recommend me some mystery and/or physiological manga? something with an ...

Can it be gory too? :O

yeah i don't mind

Then this one.~ :D
http://www.mangago.me/read-manga/kichikujima/

http://www.mangago.me/read-manga/20th_century_boys/ This takes awhile to really get going, but I promise it's worth it. (๑•ㅂ•)و✧

I have not finished it yet, but Moritat is a brain teaser

http://www.mangago.me/read-manga/sekai_oni/
http://www.mangago.me/read-manga/imawa_no_kuni_no_alice/
http://www.mangago.me/read-manga/doubt_tonogai_yoshiki/
http://www.mangago.me/read-manga/you_will_hear_the_voice_of_the_dead/
http://www.mangago.me/read-manga/homunculus/
http://www.mangago.me/read-manga/helter_skelter/

http://www.mangago.me/read-manga/bastard_hwang_youngchan/

http://www.mangago.me/read-manga/the_summer_of_the_ubume/

not sure if this is what you're looking for but if you find it interesting, there are more from the series that's not on this site.