The survivor said he hit the cougar in the head with his mountain bike, and the animal ran into the woods. But as the men were catching their breath and getting back on the bicycles, the animal returned and fastened its mouth on the man's head, crunching down, shaking him side to side like prey, Kings County Sheriff's Office Sgt. Ryan Abbott said Sunday, recalling the survivor's account.The man managed to get loose from the cougar when the animal decided to chase the man's friend, who was running away, according to Abbott. The King County Sheriff's Office said the two mountain bikers were attacked along a trail Saturday morning in North Bend, Washington. One victim was pronounced dead at the scene. The survivor was hospitalized. The suspected animal was killed."It's an incredibly tragic story," Capt. Alan Myers of the Washington Department of Fish & Wildlife said on Sunday. "It's extremely unusual for a cougar to act this aggressively on humans."Myers told CNN affiliate KOMO the men did not provoke the attack. Myers identified the deceased victim as S.J. Brooks, 32. The survivor was 31-year-old Isaac Sederbaum, Myers said.Brooks was bitten in the face, legs and neck, and Sederbaum's injuries included bite and tear marks and claw scratches on his head, neck and face, Myers said. Sederbaum underwent surgery on Sunday and remains in the hospital, according to Abbott.When the cougar released him, Sederbaum jumped back on his mountain bike to get away. As he looked back, he saw the cougar dragging Brooks into the woods, Abbott said.He rode 2 miles for cellphone reception to call 911, according to KOMO.When sheriff's deputies located Brooks, the cougar was standing on top of his body, Abbott said. Brooks had been "dragged a short distance to where the animal partially buried the body under a log," Myers said. An officer fired a shot at the cougar, which missed but spooked the animal and it ran off, Abbott said.Soon after, Fish and Wildlife dogs arrived and tracked down the cougar, who was in a tree 80 feet from Brooks' body, Abbott said. Fish and Wildlife officials euthanized the animal, Myers said. A necropsy will be performed to try to determine what provoked the attack, including any disease. Authorities said this is the second cougar attack death in Washington state in the past 100 years. Cougars are also known as mountain lions, pumas and panthers.
CNN's Darran Simon contributed to this report.