Authorities found a truck used by a suspect in the shooting deaths of four people at a bar, the bartender and three patrons, in a small town in western Montana.

Police have found the getaway car of a US military veteran who walked into a bar in the western state of Montana on Friday morning and fatally shot four people, but the gunman remains at large.

The search for the suspect continued in the mountains just west of Anaconda, where he is accused of fatally shooting four people, officials said.