Authorities were scouring a mountainous area of western Montana on Saturday for a military veteran who they say opened fire at a bar, killing four people.

Michael Paul Brown, 45, fled The Owl Bar in the small town of Anaconda in a white pickup truck but ditched it at some point, said Lee Johnson, administrator of the Montana Division of Criminal Investigation, which is overseeing the case. He urged residents late Friday to stay at home and on high alert.