There are reports on Twitter of the shooter yelling Allah Akbar, and there is a picture of a gunman with what looked like a sawed off shotgun. It is twitter so who knows.
Probably correct.................
also from Twitter, moments after the attack:
https://twitter.com/twitter/statuses/925448693624594432
Curse the Amish farmers and their tendency to yell Allahu Akbar.
If I am associating the wrong religion with that phrase, please let me know.