Suffice to say thousands of Christians have fled Mosul upon hearing this recent announcement.
There is a gruesome video circulating of Isis beheading a Christian in Syria. Not for the faint hearted. He is described as a "kaffir" or non muslim.
The argument is often made these Islamic terrorists do not represent the religion of Islam. Now, what about the Catholic crusades and mass killings of "heretics" including Jews by Inquisitions? Are they too not true Catholics? They both represent their religion and commit atrocities in its name. True believers are not organised into political movements or organised religions which are used as objects of terror against the people. We have to separate from these mass movements.
The video is here: https://www.youtube.com/watch?v=71C-wM70eE0
Warning: Not for the faint hearted.