A gunman opened fire at a neighbourhood bar in the small town of Anaconda, Montana, on the morning of Aug 1 , killing four people before disappearing into the rural foothills of south-western Montana, prompting a day-long search.

Local, state and federal agents fanned out across the region on foot, in vehicles and by helicopter in a growing chase through brushy, difficult-to-search terrain.

Residents and business owners were told to keep their doors closed and look out for the suspect, who was described as armed and dangerous.

“We’re all in the brush,” said Mr Dan Sletton, who lives near Stumptown Road west of the town, where the suspect was last seen in a white pick-up. “The guy could be 20ft (6m) from us and we wouldn’t know.”

The authorities identified the suspect as Michael P. Brown, 45. Witnesses said they heard gunshots in the Owl Bar around 10.30am local time. Brown was well known around town, and social media posts show he had been to the establishment.

Two relatives of Brown said he had served in the army for about five years until around 2006, when he returned with physical ailments and severe post-traumatic stress disorder that gave him night terrors. They said he was later diagnosed with bipolar disorder and schizophrenia.

One of the relatives, a sister who spoke on the condition that her name not be used, said that Brown would claim that famous movies had been based on his actions overseas. He sometimes told people that he was Jason Bourne, or a five-star general on a secret mission.

The sister and other family members had tried to get help for Brown from the Department of Veterans Affairs, she said, but without Brown’s cooperation, little could be done.

Mr Tobe McHugh, 48, and Mr Tyler Edwards, 25, two mechanics in the area, said Brown had, in the past, told them wild stories, including about being a professional golfer or completing secret missions.

“He’s a calm guy, but he’s out there,” Mr McHugh said as he stood outside another bar down the street from the Owl. “He was always telling stories.”

Brown grew up mostly in Anaconda, a former copper smelting town near Butte in Deer Lodge County, with a population of about 10,000. Records show that he lived just two houses down from the Owl Bar, a local dive with a pool table, a clutter of decorations and a sign out front that boasts the “best tap beer in town”.

On the evening of Aug 1, the bar was surrounded by police tape and law enforcement vehicles, with TV cameras lined across the street awaiting news on the search. More police officers and federal agents continued to stream in, including from Missoula, about a 1½-hour drive north-west.

“I’m constantly hearing sirens go off every 10 or 15 minutes,” said Mr Brandon Baragar, 32, who lives in the search area. “They’re looking, just trying to find a needle in a haystack.”

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