The bear responsible for Wednesday’s fatal mauling south of West Glacier remained at large Thursday night as state wildlife officials headed home empty-handed after a full day scouring the area in the Flathead National Forest near the scene of the attack.

It was the second day spent searching from both the ground and the air after a bear — initially reported by law enforcement as a grizzly — attacked and killed a mountain biker Wednesday afternoon in the Green Gates/Half Moon trail area.

The area surrounding the scene of the attack, extending east and south from U.S. 2 in the West Glacier area toward Desert Mountain, has been closed to public use by the Flathead National Forest. The roughly 10-square-mile closure is bounded to the east by the Great Bear Wilderness and to the south by the Coram Experimental Forest.

Brad Treat, 38, a law enforcement officer with the U.S. Forest Service, was pronounced dead at the scene after he was attacked while riding his mountain bike Wednesday afternoon.

The bear knocked Treat off his bike and killed him; the bicyclist riding behind him was not attacked and rode back to summon help.

Montana Fish, Wildlife and Parks spokesman John Fraley said Thursday the state wildlife agency had deployed its Wildlife Human Attack Response Team, consisting of about a half-dozen agency personnel, to comb the area near the attack.

“We have biologists and wardens that have been specifically trained on how to respond to these incidents,” Fraley said.

He said three or four culvert traps had been set by Thursday night, but he did not know how long the team would continue to actively search the area.

Remote motion-sensor cameras have also been set up in the area. Fraley said agency personnel collected bear DNA samples to help identify any bears the team catches, but he noted the results would not be available for about a week.

Flathead County Sheriff Chuck Curry, whose office is assisting state wildlife officials and the Forest Service, said Two Bear Air Rescue helicopters searched for the bear Thursday morning.

Fish, Wildlife and Parks had not confirmed whether the animal responsible for the attack was a grizzly or a black bear, Fraley said. That determination will rest on the DNA samples and other evidence collected from the scene.

“We are attempting to capture and/or confirm the identity of the offending bear,” Warden Capt. Lee Anderson of Montana Fish, Wildlife and Parks said in a Thursday news release. “When we have more information we will decide what actions to take.”

A large grizzly bear had been reported Wednesday afternoon in a marsh near the scene of the lethal bear mauling while crews searched for Treat, but Curry said searchers did not know whether it was the bear involved in the attack.

“There was a bear sighted by [medical helicopter] ALERT, but again, is it the right bear? There’s a lot of bears up there,” Curry said.

Fish, Wildlife and Parks spokesman Ron Aasheim said Thursday that the area is dense with bears and it may be difficult to find the one that killed Treat.

Bears that attack people are killed if wildlife managers determine that they displayed predatory behavior, such as stalking the person, or consumed their victim.

In this case, officials said is too soon to say what will be done to the bear if it is found. They are trying to determine if it was a mother with cubs, whether it was protecting a food cache nearby or whether it simply reacted to the surprise appearance of the bikers, Aasheim said.

“One of the things that is key to all this is whether it was a predatory act,” Aasheim said. “I don’t think there’s any sense that this was predatory.”

To confirm whether they have the right bear, wildlife officials typically collect DNA evidence from the animal to compare it to evidence found at the scene, analyze bite marks and other injuries on the victim, and examine the animal’s claws, jaws and feces for human remains.

An autopsy was being performed on the victim at the state crime lab, and the evidence gathered could help determine the size, age and sex of the bear, narrowing the search, Curry said.

The Associated Press contributed to this story.