After nearly a dozen people were stabbed at a Walmart in Traverse City, Michigan, Saturday afternoon, the quick actions of a couple of Marines and other bystanders helped stop the attacker from causing further harm.

Eleven people were taken to Munson Medical Center in Traverse City after a man stabbed shoppers in a nearby Walmart store.

The authorities on Sunday said that a motive for the attack, which left 11 people injured, remained unknown. Citizens, including one who was armed, helped to apprehend the suspect, officials said.