Dembele refused to attend training in the final days of the summer market as he forced through a move to Barca.
"I'm to blame because the advisers have made sure he does not train with Dortmund! The advisers! The behavior of the player is not clear to me.
"He unjustifiably refused to train with Borussia Dortmund, and obviously it is a conscious decision. This behavior must be punished. I would immediately part from a player who does this. How far will we go?"