There's a big clue what happened. People don't hunt inside town. If there are little warheads scattered about, it was likely tribal warfare. Will future archeologists find shell casings in downtown Detroit and conclude they had a hunting economy that mysteriously came to an end?
Yup. A site in what’s now Egypt had been a good-sized Neolithic town about 15,000 years ago; the entire place was burned to the ground and never rebuilt. In the ash layer were found thousands of spear- and arrowheads from the terminal events.