The search for a former U.S. soldier suspected of killing four people at a bar in Montana stretched into a fourth day Monday, with deputies scouring the mountainous terrain by foot and air after the man escaped in a stolen vehicle containing camping gear.

Authorities say Michael Paul Brown, 45, fatally shot four people Friday morning at The Owl Bar in the small town of Anaconda with a rifle that police believe was his personal weapon. He fled in a white pickup that he later ditched and stole a car stocked with clothes, shoes and other supplies.

A female bartender and three male patrons were killed. The shooting rattled the tight-knit town of about 9,000 people, and many residents remain on high alert with the suspect still at large.

Here’s what is known about the search.

How is the search progressing?

Law enforcement officers from across the state have been brought in to assist with the search for Brown, Montana Attorney General Austin Knudsen said. Search teams include multiple local, state, and federal agencies and are surveying the area both on the ground and by air. Helicopters whirred overhead throughout the weekend as Anaconda residents adjusted to daily life after the shooting.

The effort initially concentrated on an area off Stumptown Road, west of Anaconda. Knudsen said investigators are now searching all possible options for Brown’s whereabouts, including the woods where he hunted and camped in his youth. They suspect he may be armed.

The woods southwest of Anaconda have been closed to the public by the National Forest System as the manhunt carries on.

Business owners locked their doors Friday and sheltered inside with customers. A lockdown of the Stumptown Road area was lifted on Saturday, but many local businesses were slow to reopen.

Who were the victims?

The victims were identified on Sunday as Daniel Edwin Baillie, 59, Nancy Lauretta Kelley, 64, David Allen Leach, 70, and Tony Wayne Palm, 74.

All four were residents of Anaconda, which is situated between rugged mountains about 25 miles (40 kilometers) northwest of Butte.

Robert Wyatt, 70, said he was neighbors with Leach at a public housing complex for elderly people and people with disabilities. Leach was deaf and kept mostly to himself, Wyatt said, but he was always happy to help his neighbors.

In a town where “everybody knows everybody,” the entire community is hurting, said resident David Jabarek, 70.

What is known about the suspect?

Brown served in the 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 and left military service at the rank of sergeant, Castro said.

Brown lived next door to The Owl Bar, according to owner David Gwerder, who was not present during the shooting Friday morning. It was widely believed that Brown knew at least some of the victims.

In a photo released by law enforcement, Brown appears gaunt, barefoot and wearing nothing but black shorts.

Brown’s niece, Clare Boyle, told The Associated Press that her uncle has struggled with mental illness for years, and she and other family members repeatedly sought help for him.

He was known to local law enforcement before the shooting, Knudsen said. There is a $7,500 reward for any information leading to Brown’s capture.