Wildlife response team investigator Brian Sommers said in a statement today that he believes Brad Treat was riding at a high rate of speed along a narrow trail and hit the bear. Visibility was limited and investigators believe the collision was unavoidable.

• See how fast it can happen in this biker's collision with a black bear, posted on YouTube last week (in this case, the biker was not seriously injured and the clobbered bear ran away):

Treat, who was a law enforcement officer with the U.S. Forest Service, was found dead Wednesday by officers at the scene of the mauling. Treat’s riding companion reported the incident and was not attacked.

Montana Fish, Wildlife & Parks spokesman Ron Aasheim called the event a tragic accident. Investigators are still trying to determine if it was a black bear or a grizzly, and whether it might have been a female bear trying to protect her cubs. Investigators have removed cameras that were being used to find the bear, along with traps that were placed in the area.

“This is an area of pretty high density of bears, and the bear didn’t return,” Aasheim told the Associated Press. “It was just a horrible accident. The bear was in a defensive mode responding.”

Authorities are still awaiting DNA tests that will show if the bear was male or female, and whether records show it might have been responsible for previous attacks.

The attack occurred in a heavily forested area, and the area has been closed off, said National Forest spokeswoman Janette Turk.

An autopsy on Treat could help determine the size, age and sex of the bear, Flathead County Sheriff Chuck Curry said.

Treat became a Forest Service law enforcement officer in 2004. He spent the last 12 years stationed at the remote Hungry Horse District in the Flathead National Forest, where the territory stretches into the untamed Great Bear Wilderness.