Paul Hanson / AP

This undated photo provided by Paul Hanson shows his sister, Dianna Hanson, a 24-year-old intern at the Cat Haven in Dunlap, Calif., who was killed by a lion .

SAN FRANCISCO — A 24-year-old intern killed by an African lion at a California wildlife sanctuary died suddenly after the big cat broke her neck, a coroner said on Thursday as investigators probed why the worker had been inside the animal's enclosure.

The Cat Haven sanctuary east of Fresno remained closed on Thursday, a day after Dianna Hanson was killed by a 350-lb male Barbary lion named Cous Cous that attacked her inside a pen. Hanson was from the Seattle area.

"The young lady did not suffer because she died almost instantly from a fractured neck," Fresno County Coroner Dr. David Hadden told Reuters.

An autopsy conducted on Thursday showed bite and claw marks on Hanson from "the lion playing with the body like a cat would play with a mouse," Hadden said.

The coroner also said the lion escaped its cage to kill Hanson while she was cleaning the enclosure.

The California Division of Occupational Safety and Health sent two inspectors with questions such as whether the sanctuary allowed the woman to enter the enclosure, said agency spokesman Peter Melton.

"We'll find out exactly what she was doing and what her job duties were and whether she was following the procedures as they were supposed to be done," Melton said.

The death was the latest of a handful of high-profile incidents involving big cats in captivity in the United States in recent years, and comes less than six months after a man leapt into a tiger's den at the Bronx Zoo, sustaining multiple injuries.

Hanson's Facebook page showed pictures of her standing or sitting next to big cats, apparently in enclosures, and she had worked on a wild feline reserve in Africa. Her father has told a television station she liked to get close to big cats.

"I've always had a premonition this would happen," Paul Hanson told Seattle television station KING 5. "She really loved getting up close and personal with the animals."

Stringer / Reuters

A security guard stands by the gate of the Cat Haven sanctuary near Dunlop, California, March 7.

Cat Haven is a 100-acre sanctuary in Dunlap, California, run by the group Project Survival. 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 the park's website.

Dale Anderson, founder of the facility, told reporters outside the gates of his facility that he could not comment on the circumstances of Hanson's death or the safety protocols at Cat Haven. "Our whole staff is just ... it's devastating," he said as he broke down in tears.

Passion for cats
Hanson, who graduated in 2011 from Western Washington University with a degree in biology, had spent six months in Kenya last year working on a wild feline reserve.

In 2011 and 2012, Hanson also volunteered in Seattle for the Snow Leopard Trust, which seeks ways to protect the endangered species, the organization said.

The 4-year-old Barbary lion that killed Hanson was of a species that is extinct in the wild, said Janice Mackey, a spokeswoman for the California Department of Fish and Wildlife, which oversaw 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.

The lion was shot and killed by sheriff's deputies as they tried to reach Hanson, authorities said. On Thursday, a necropsy was performed on the lion to determine if it suffered from any health problems that could have led to the attack, Mackey said.

Anderson, Cat Haven's founder, said the facility has been "incident free" since it opened in 1998, and California officials confirmed they had never responded to any emergency at the facility similar to Wednesday's death.

The death comes less than six months after a man leapt into a Siberian tiger's den at the Bronx Zoo and sustained multiple injuries. In 2010, a lion attacked a trainer at a glass-encased enclosure at the MGM Grand in Las Vegas. The trainer survived.

In another high-profile incident involving captive cats in 2011, the owner of a private menagerie released dozens of tigers, lions and other animals in Ohio, and then killed himself. The case led some animal welfare groups to call for a ban on private ownership of exotic animals.

The California Department of Fish and Game permits private animal sanctuaries only if their goal is scientific research or public education, Mackey said.

Additional reporting by Stephen Keleher in Dunlap, California, and Laura L. Myers in Seattle