Write a letter Santa telling him what you done stay up on Christmas Eve and hand his body over to Santa, if he comes. Tell him you hadn't realised what he was until it was too late and make sure he understands you were only trying to protect your family most parents would have done the same given the chance

Op I'd advise trying to bring this santa cult to justice or get vengeance for wally. Don't do it on your own though try and form a sort of militia or paramilitary organisation do this in secret and then go undercover in their cult make any one who joins your organisation do the same and take them down from the inside.