The former US soldier suspected of killing four people at a Montana bar was still at large early Sunday and may be armed after escaping in a stolen vehicle containing clothes and camping gear, officials said. Authorities believe 45-year-old Michael Paul Brown killed four people on Friday morning at The Owl Bar in Anaconda, Montana, about 120 kilometres southeast of Missoula in a valley hemmed in by mountains.

Montana Attorney General Austin Knudsen said at a press conference Sunday that Brown committed the shooting with a rifle that law enforcement believes was his personal weapon. The victims ranged in age from 59 to 74 and were a female bartender and three male patrons. Knudsen warned residents in the town of just over 9,000 people that Brown, who lived next door to the bar where he was a regular, could come back to the area.

'This is an unstable individual who walked in and murdered four people in cold blood for no reason whatsoever. So there absolutely is concern for the public,' Knudsen said. Numerous public events were cancelled over the weekend as the search entered its third day, according to local Facebook pages. Investigators are considering all possible options for Brown's whereabouts, the attorney general said.