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

A weekend stabbing spree at a Michigan Walmart initially left 11 injured, including six critically. As of the latest update, 10 people remain hospitalized and are being treated for their injuries, according to officials. The attack began at the Traverse City store around 4:43 p.m. local time on July 26.

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