ANACONDA, Mont. — Authorities are currently searching a mountainous region in western Montana for a military veteran who they report is responsible for a fatal shooting at a local bar, resulting in four deaths.

According to Lee Johnson, administrator of the Montana Division of Criminal Investigation leading the case, 45-year-old Michael Paul Brown escaped The Owl Bar in Anaconda using a white pickup truck but later abandoned the vehicle. Johnson has advised residents to remain indoors and exercise extreme caution.

“Although there have been no further reports of Brown harming others, he is considered to be armed and presents a severe danger,” Johnson stated.

Authorities said they would release the names of the victims once all of their families have been notified.

He remarked, “This closely-knit community is reeling from the deplorable actions of an individual whose behavior does not reflect the values of this town or those of Montana as a whole.”

Anaconda, a town located approximately 25 miles (40 kilometers) northwest of Butte, is surrounded by mountain ranges. With a population of about 9,000, it has historical roots dating back to the late 1800s when it was founded by copper magnates benefiting from nearby mining operations. An inactive smelter stack still stands over the valley.

The Owl Bar’s owner, David Gwerder, who was not present during the shooting on Friday morning, reported that the bartender and three bargoers lost their lives. He indicated that he believed no one else was present at the time. Gwerder also mentioned being unaware of any prior disputes between Brown and the victims.

“He knew everybody that was in that bar. I guarantee you that,” Gwerder said. “He didn’t have any running dispute with any of them. I just think he snapped.”

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

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

“This isn’t just a drunk/high man going wild,” she wrote 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.”

With no sign of Brown in the white pickup or his home, authorities converged on the Stumptown Road area west of Anaconda by ground and air, locking it down so no one was allowed in or out. A helicopter hovered over a nearby mountainside as officers moved among the trees, said Randy Clark, a retired police officer who lives there.

As reports of the shooting spread through town earlier Friday, business owners locked their doors and sheltered inside with customers.

The owner of the Firefly Café in Anaconda said she locked up her business after a friend alerted her to the shooting.

“We are Montana, so guns are not new to us,” Barbie Nelson said. “For our town to be locked down, everybody’s pretty rattled.”