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.

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.

The man was captured in three minutes thanks to "citizen involvement," Grand Traverse County Sheriff Michael D. Shea said.