Derrick Perry, a United States Marine veteran, confronted a knife-wielding man in the parking lot of the Traverse City Walmart.

By the time an employee in the checkout area yelled about a man with a knife, it was too late. Nearly a dozen people had been stabbed at the busy Walmart in Traverse City, a tourist town on the shore of Lake Michigan, by a man who appeared to have attacked people at random, the sheriff said.

Matthew Kolakowski was shopping with his daughter at a Michigan Walmart when he heard screams and saw a man with a knife.

The suspect at times went off on tangents about cigarettes filled with fiberglass and seeing videos about psychotropic drugs.