Patrick Cooper had already turned around after reaching the halfway point in a popular mountain race in Alaska when he somehow veered off the trail and became lost. That's when the 16-year-old Anchorage boy encountered the black bear that would take his life in a rare predatory attack.

Cooper began running, and at one point he reportedly placed a frantic call to his brother, saying he was being chased by a bear Sunday in the Robert Spurr Memorial Hill Climb race south of Anchorage. The brother notified race director Brad Precosky, who alerted race crews to begin searching for Cooper, known as Jack.

It took a couple hours for responders to locate the teen, whose body was found about a mile up the path, at about 457 vertical meters. The bear was found at the site, guarding the body, Precosky said.

Bear Mauling Teen Dies

A jogger runs across the Sterling Highway, near a trail head that's closed after a fatal bear mauling at Bird Ridge Trail in Anchorage, Alaska. Authorities say a black bear killed 16-year-old Patrick Cooper while he was competing in an Alaska race on Sunday. (Mark Thiessen/The Associated Press)

A Chugach State Park ranger shot the 250-pound bear in the face, but the animal ran away.

Alaska State Troopers said the boy's remains were airlifted from the scene on Sunday. State park staffers were scouring the area Monday looking for the bear, state Fish and Game spokesman Ken Marsh said.

Sunday's attack was believed to have been a rare predatory move, not a defensive action such as when a female bear will protect her cubs, he said.

"It's very unusual," Marsh said of the mauling. "It's sort of like someone being struck by lightning."

Not normal behaviour

Matt Wedeking, division operations manager with Alaska State Parks, said the bear's predatory behaviour was not normal. Asked if there were cubs around this black bear, he said, "We don't know. There could have been. But right now I don't have any information about the bear."

The last fatal mauling in the state occurred near Delta Junction in Alaska's interior in 2013, when a man was killed by a male black bear, Marsh said. The last fatal bear attack in the greater Anchorage area was in 1995, when two people were killed in the Turnagain Arm area by a brown bear protecting a moose carcass, he said.

Last week, a juvenile and two young adults sustained minor injuries when a female brown bear with two cubs attacked them. Authorities shot at that bear, but it ran off.

Areas where wilderness races such as Sunday's take place are inherently risky when it comes to bear encounters, Precosky said.

Anchorage Girdwood Alaska map

Cooper was a participant in the juniors division of the Robert Spurr Memorial Hill Climb race between Anchorage and Girdwood. (CBC)

Competitors in the Bird Ridge race sign a liability waiver as part of the registration process.

But competitors often train alone in such areas and are fully aware of the dangers. Races actually can be said to cut down on the risk of a bear encounter because so many people are there, making noise and making their presence known, Precosky said.

"There's no safer time to be on a mountain than on a race," he said.

Earlier reports say Cooper texted his mother that he was being chased by the bear, but Precosky said he could not confirm that.