Quote from : The True Jihad: The Concept of Peace, Tolerance and Non Violence in Islam Book

Not all Muslims become involved in acts of violence. Yet all might be held culpable. THis is because that section of Muslim--in fact, the majority--who are not personally involved, neither disown those members of their community who are engaged in violence, nor even condemn them. In such a case, according to the Islamic Shariah itself, if the involved Muslims are directly responsible, the uninvolved Muslims are also indirectly responsible. (p. 91)