A mountain lion attacked and severely injured a bicyclist in an Orange County, Calif., park and may have killed a man whose body was found nearby, authorities said Friday.Authorities shot and killed a 2-year-old, 110-pound, male cat hours later near where the man's body was found. They were "pretty confident" it was the animal that attacked and took it to a laboratory for testing on Friday, said Steve Martarano, a spokesman for the California Fish and Game Department.Anne Hjelle had been riding with a friend in Whiting Ranch Wilderness Park shortly before dusk Thursday when the mountain lion attacked her, said Orange County Fire Capt. Stephen Miller.The lion pounced on the 30-year-old's back, grabbed her by her head and began dragging her, said her friend, Debbie Nichols. Nichols said she screamed for help and grabbed Hjelle's legs in a struggle to free her."He dragged us down ... about 100 yards into the brush and I just kept screaming," Nichols said. "This guy would not let go. He had a hold of her face.""He had Ann's face completely in his jaws. It was a tug-of-war," another witness said.Other cyclists in the area threw rocks at the animal until it fled."I picked up a rock and threw it at the cat and the rock hit the cat right on the side of the head and the cat took off straight ahead and let go of the woman," Diego Lopez said.Hjelle was airlifted to Mission Hospital, where she was in serious condition early Friday, a nursing supervisor said.After the attack, the body of an unidentified man in his 30s was found at the top of a trail near a bicycle. Authorities weren't sure how long he had been there and couldn't confirm if the man was killed by the mountain lion, but Miller said, "it's pretty obvious that an animal was involved." An autopsy was planned Friday.Authorities said a second mountain lion in the area was hit by a car and killed late Thursday and would also be tested.The park was closed Friday morning and will remain closed until authorities can determine if the animal killed was the one responsible for both attacks. A news conference to discuss the case was scheduled for Friday.Including Thursday's incident, there have been 13 mountain lion attacks on humans in California over the past 114 years, said Doug Updike, a biologist with California Fish and Game Department. In those cases, there were five fatalities, he said."The probability of somebody being attacked by a lion is extremely rare," Updike said. "There is a better chance of being struck by lightning than being attacked by a lion."Thursday's attack was in a southern Orange County park adjacent to the communities of Foothill Ranch and Portola Hills and Cleveland National Forest.Suburban tract homes are located just a couple of miles away from where Thursday's attack took place.Although the number of attacks is comparatively small, there have been previous sightings and attacks nearby.Last September, game wardens shot and wounded an aggressive mountain lion spotted near an equestrian center in San Juan Capistrano. The lion was later found and killed, state officials said.In 1986, 5-year-old Laura Small was attacked while looking for tadpoles with her mother in Ronald W. Caspers Wilderness Park in Orange County.The girl's mother was able to rescue her daughter whose skull was partially crushed by the mountain lion's jaws. She was left blind in one eye and paralyzed on her right side.Months later, a 6-year-old boy was mauled in the same park. County supervisors closed most of the park to children for nearly a decade. The ban was lifted in December 1997.Three years later, a state law was passed prohibiting people from hunting or killing mountain lions.The threat of mountain lions has become an increasing problem in Southern California as development encroaches upon rural areas that have been home to various animals.Updike estimates there are between 4,000 and 6,000 adult lions roaming the Golden State, with usually five to seven mountain lions per 100 square miles.