(CNN) The stabbing attack at the Crossroads Center mall in St. Cloud, Minnesota, could have been much worse, if not for the actions of an off-duty police officer.

That officer -- identified as Jason Falconer -- fatally shot Dahir Adan on Saturday after Adan had already stabbed nine people and threatened other shoppers.

Here's what we know about Falconer:

He's a firearms training instructor

He owns a firing range and firearms training facility called Tactical Advantage . He's considered an expert in firearms training and education and has helped teach classes on law enforcement skills at St. Cloud State University for nine years, his company website says.

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