The former U.S. 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 75 miles (120 kilometers) 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. All the victims were adults between 50 and 70 years old. One of the victims was the bartender.

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 canceled 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. That includes searching the woods where Brown hunted and camped while he was a kid. But Knudsen noted that, during peak tourist season in western Montana, some law enforcement officials would have to return to their local jurisdictions for their regular responsibilities.

Brown served in the Army as an armor crewman from 2001 to 2005 and deployed to Iraq from early 2004 until March 2005, according to Lt. Col. Ruth Castro, an Army spokesperson. Brown was in the Montana National Guard from 2006 to March 2009, Castro said, and left military service at the rank of sergeant.

Brown’s niece, Clare Boyle, told the AP her uncle has struggled with mental illness for years and she and other family members repeatedly sought help.

“This isn’t just a drunk/high man going wild,” she said in a Facebook message. “It’s a sick man who doesn’t know who he is sometimes and frequently doesn’t know where or when he is either.”

Knudsen said on Sunday that Brown was “known” to local law enforcement before the shooting. It was widely believed that he knew at least some of the victims, given how close he lived to the bar.

Law enforcement released a photograph of Brown from surveillance footage taken shortly after the fatal shootings. He appeared to be barefoot and in minimal clothing.

But law enforcement now believes Brown ditched the vehicle he escaped in and stole a different one that had camping gear, shoes and clothes in it — leaving open the possibility that Brown is now clothed.

The last time that law enforcement saw Brown was on Friday afternoon, but there was “some confusion” because there were multiple white vehicles involved, Knudsen said.

There is a $7,500 reward for any information that leads to Brown’s capture.

“This is still Montana. Montanans know how to take care of themselves. But please, if you have any sightings, call 911,” Knudsen said.