Court records show the man charge with stabbing 11 people at the Traverse City Walmart was treated for a year at a mental health facility after breaking into a grave.

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.

"I'm still sitting and grappling with the weight of realizing that it was kind of a life-or-death moment," said Julia Martell, who witnessed the stabbing, which wounded 11 people.