I guess muslims say peace be upon him when referring to Muhammad, because the guy obviously doesn't know the meaning of of the word 'peace':
"Kill them wherever you may find them ..."
Two killed in Iraq attacks on Christian homes
Two people have died and 14 injured in a series of attacks on Christian homes in the Iraqi capital, Baghdad.
http://www.bbc.co.uk/news/world-middle-east-12096078