"Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken and by wicked hands have crucified and slain." -Acts 2:23
Man is responsible for the positioning of His heart, the condition that inclines him to move his hand. The act itself is not the cause of the act.
Monergist concerning Salvation and a monergist concerning guilt; God is the author of Salvation and Man is the author of guilt.