Parts of a national forest near Anaconda, Montana, were closed late Saturday as authorities expanded their search for the gunman accused of killing four people at a bar on Friday morning.

The suspect, identified as Army veteran Michael Paul Brown, was seen on security footage fleeing The Owl Bar, where the fatal shooting occurred, investigators said. He was last seen in the Stump Town area, west of Anaconda, according to The Associated Press.

Authorities have locked down Barker Lake and the surrounding area inside the Beaverhead-Deerlodge National Forest as local, state and federal agencies continue their search by land and air, a Montana Department of Justice spokesperson said.

On Friday, local law enforcement warned that Brown is “armed and extremely dangerous.”

“It’s okay to go about your business in town but please use caution,” Anaconda Deer-Lodge County Chief Bill Sather said in a Saturday update on Facebook, urging residents to call 911 if they see the gunman.