. . and the Christians, God is omnipotent and omnipresent, thus totally responsible for all acts including those of "that other guy". It follows that all your or anyone else's inflictions are inflicted by God.
Any denial of this by God would imply He is not omnipotent and omnipresent, demonstrating that He is not God. Any denial of this by anyone other than God would be a claim God is not God, and that would be blasphemy.