[UPDATED: 4:19 p.m., 10/15/12]

A Sitka man is dead after an encounter with a brown bear. Authorities spent Monday searching southern Chichagof Island, near Sitka, for the animal believed to be responsible in the fatal mauling of a 54-year-old Tomas Puerta.

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On Sunday, a good Samaritan vessel noticed an unsecured skiff on the beach near Poison Cove. That’s on southern Chichagof Island, about 30 miles north of Sitka.

“When they were taking a look and investigating that, they had gone back in the woods a little bit farther, and hollered, and ended up startling a sow and cub,” Sitka Mountain Rescue Capt. Don Kluting said. “Things just didn’t seem right to them, so they went back out to their boat and notified Coast Guard sector Juneau.”

The Coast Guard called Sitka Mountain Rescue, and they along with Sitka police and an Alaska State Trooper responded.

Sitka police said in a statement that responders found a campsite with evidence of a struggle. A trail of disturbed vegetation and articles of clothing led responders to a brown bear cache, which contained partially consumed human remains.

Puerta was tentatively identified based on items found at the scene and information from his friends and family. His remains were flown to the state Medical Examiner’s office in Anchorage, which will confirm his identity.

Kluting was one of the first people on scene, and he says things looked amiss even from the beach, where the engine cover on the 13-foot skiff had been removed and placed inside the boat.

“We don’t have confirmation or anything, but it certainly appears like there was a mechanical problem, and the motor was in the down position, and it ended up on the beach in that location,” Kluting said. “I can certainly understand why the reporting party went ashore to take a look and investigate initially. It was precarious; it wasn’t normal. It’s not how somebody would normally anchor a boat and leave it.”

Investigators are continuing to piece together what happened on shore. Puerta was working under contract with the Forest Service doing some tree-thinning work in the Tongass National Forest.

The incident took place in a triad of islands known as “the ABCs.” That stands for Admiralty, Baranof, and Chichagof. The three islands are among the most densely populated brown bear habitats in the world.

Still, violent encounters between bears and humans are rare occurrences.

The last fatal bear encounter in the ABC islands was in 1988, when a 40-year-old hunter was killed by a brown bear while hunting alone near Port Alexander. The last fatal bear encounter in Southeast Alaska occurred in 2000, in Hyder. A man in a campground was killed by a bear frequenting a nearby landfill.

“In most cases, when bears and people come in contact, it’s sort of reciprocal: both want to get out of one another’s way, and bears typically will flee, assuming they’ve got a place to get away to or an avenue out,” said Doug Larsen, Southeast regional supervisor for the Alaska Dept. of Fish & Game’s wildlife conservation arm.

Larsen says there are exceptions to fleeing, of course, such as when a sow is guarding her cubs, or a bear feels its food source is threatened.

“And when they’re surprised to where they don’t have a place they can flee to,” he said. “Then it’s that fight or flight, and in those cases, there have been instances where a bear will come after a human, basically to protect themselves.”

But Larsen also stresses that he’s speaking generally about bear behavior. Fish & Game is not yet involved in this case, and too little is known right now to determine why a bear might have killed Puerta.

Sitka police and state troopers continue to investigate, and spent Monday looking for the bear or bears that might have been responsible. Standard practice after a fatal bear encounter with a human is to kill the bear involved. Larsen says that’s partly to learn more about why the bear was behaving aggressively, and partly to prevent it from happening again.

KCAW’s Anne Brice contributed to this report.