Who symbolically placed all the sins of Israel on the scapegoat?
The High Priest alone, according to the ritual described, laid his hands on the scapegoat and symbolically placed all the sins of Israel upon it. Only he could enter behind the veil and sprinkle blood on the mercy seat; that scapegoat ceremony was exclusively his work.
Les explains that in Israel's ritual, one goat was killed and its blood was sprinkled on the mercy seat behind the veil, while the other goat, the scapegoat, had the sins of Israel symbolically placed on it. Only the High Priest could go in behind the veil, sprinkle the blood on the mercy seat, and lay his hands on the scapegoat. That was the work of the High Priest alone.