Was because he was the one that torture Yamori!! Σ(っ°Д °;)っ i´m sure of it.
http://www.mangago.zone/read-manga/tokyo_ghoul/tr/v07/c061/1.html/pg-13/
It's the guy Haise was talking to, Tokage Goumasa's hand. Yamori indeed picked up his finger cracking habit from him, as I'm positive he mentions to kaneki he picked up that habit from his interrogator (the man Haise is seen talking to in that section) during his time in captivity. As well as the whole counting backwards thing. Kaneki then proceeded to pick up those traits from Yamori. Haise doesn't have those traits, but Kaneki does, as you can see whenever he reverts back to him for any short period of time.
can someone look this page closely I though it was haise finger , but not ...
why tht guy ... ??'''
http://www.mangago.zone/read-manga/tokyo_ghoulre/bt/v04/c037/pg-12/