A former Marine who helped confront the suspect in a stabbing rampage at a Walmart in Michigan spoke with "Good Morning America" after the incident that authorities said was an act of terrorism.

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

Video shows an armed bystander confronting a knife attacker who allegedly injured 11 people at a Walmart in Traverse City, Michigan, on Saturday.