(New throughout, adds results from necropsy examination of lion)
By Laila Kearney
SAN FRANCISCO, March 8 (Reuters) - The African lion that killed a California wildlife sanctuary worker had slipped out of its holding pen, which apparently was left improperly secured, and crept up on the woman inside a larger enclosure to attack her, the coroner said on Friday.
Dianna Hanson, 24, an intern at the Cat Haven sanctuary east of Fresno, died almost instantly on Wednesday after the big cat, a male named Cous Cous weighing at least 400 pounds (181 kg), snapped her neck, according to an autopsy conducted on Thursday.
Hanson was cleaning the larger enclosure when the lion escaped from its holding pen, apparently by lifting a gate that slides open and shut vertically, Fresno County Coroner Dr. David Hadden told Reuters.
"The gate is kind of like a guillotine. It comes down and hits the base of the ground. If that gate wasn't all the way down, the lion could have put its paw under the gate and pushed it up, and the gate is designed so that it would stay up," he said. Hadden said the lion was being fed at the time, though he was not sure if Hanson was the one who left food for the animal.
"The lion did not touch its food. It was more interested in what she was doing, and it ran in and attacked her," he said. "she had been talking on her cell phone shortly before the attack and we found a damaged cell phone on the scene."
On Thursday, Hadden said autopsy results showed the intern, who was from the Seattle area, "died almost instantly from a fractured neck." He added that the autopsy also showed bite and claw marks on Hanson from "the lion playing with the body like a cat would play with a mouse."
Sheriff's deputies shot and killed the lion as they tried to reach Hanson, authorities said.
State officials on Thursday performed a necropsy, the animal equivalent of an autopsy, and found the lion to be in "good body condition," with solid muscle composition, a healthy coat and proper nourishment, Janice Mackey, a spokeswoman for the California Department of Fish and Wildlife, said on Friday.
A pathologist also examined the lion's brain and took tissue, blood and hair samples to determine whether any underlying health issues, such as neurological disorders or diseases like rabies, might have caused the attack. Full test results are not expected for a couple of weeks, Mackey said.
The initial necropsy report put the lion's weight at between 400 and 500 pounds, heavier than the 350 pounds earlier cited by authorities.
Hanson had begun what was to be a six-month internship at the private sanctuary in January after spending six months in Kenya last year working on a wild feline reserve. She earned a biology degree in 2011 from Western Washington University.
Cat Haven, a 100-acre (16-hectare) sanctuary in Dunlap, California, run by the group Project Survival, has been closed until further notice. It was founded "to exhibit a variety of wild cats and engage public support for their conservation in the wild via specific projects," according to its website.
On Thursday, Cat Haven founder Dale Anderson told reporters he could not comment on the circumstances of Hanson's death or the sanctuary's safety protocols. "Our whole staff is just ... it's devastating," he said as he broke down in tears.
He said the facility has been "incident free" since opening in 1998, and California officials confirmed they had never responded to any emergency there prior to Wednesday's death.
The 4-year-old Barbary lion that killed Hanson was of a species that is extinct in the wild, said Mackey, whose agency oversees the permit that allows the sanctuary to operate.
The lion had been handled by humans since it was weeks old, and was one of two Barbary lions at the facility. Several years ago, when it was a cub, Cous Cous also made an appearance on the talk show "Ellen," Mackey said. (Additional reporting by Stephen Keleher in Dunlap, California; Laura L. Myers in Seattle and Dan Whitcomb in Los Angeles; Writing by Alex Dobuzinskis; Editing by Cynthia Johnston, David Gregorio and Lisa Shumaker)