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

Nearly a dozen people were injured in the attack before citizens -- including Derrick Perry, who was armed with a gun -- confronted the suspect, authorities said.

A Walmart employee was helping a customer check out when she heard a warning that someone in the store had a knife.

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