One of the men who authorities say helped take down a suspect who stabbed eleven people at a Walmart told NBC News about how he sprung into action. Marine veteran Matthew Kolakowski says he took off running after the suspect and rammed him with a grocery cart to prevent him from hurting more people.

Police are trying to determine why a man allegedly traveled downstate to Traverse City and stabbed 11 people inside a Walmart.

"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.