Anybody Ever Seen This Before?

If the chain broke first, how did a tooth end up between the chain and the cam sprocket? The tooth broke first, and was carried by the chain to where it sits in the picture (or maybe a lap or two and then where it sits, but at least to where it sits). Also, if the chain broke first while everything was moving at speed, it wouldn't have been just hanging on the cam gear. Assuming the first picture is how Rob found it, the chain had to let go when everything had nearly stopped spinning. Otherwise the rotating gears would have just shed the chain and it would have been wadded up at the bottom of the cover. Also, if the chain got wedged somewhere, there would be a witness mark on the block or the gear where that happened.