Police have arrested a 47-year-old man who allegedly killed three people Wednesday evening after seemingly firing at random in a suburban Denver Walmart. Scott Ostrem was arrested early Thursday morning after police say he calmly walked to the front of the store and allegedly began shooting his handgun, killing two men and one woman. “He walked in very nonchalantly with his hands in the pockets, raised a weapon and began shooting. Then he turns around and walks out of the store,” said Victor Avila, a spokesperson for Thornton police. “From what we have right now it appears to be random. It’s a crazy world we live in.” Ostrem reportedly declared bankruptcy in 2015 and was arrested for driving while impaired in 2013.