Los Angeles (CNN) A mountain lion miraculously surviving in the urban mountains here is believed to have breached a 9-foot fence at the Los Angeles Zoo and mauled an 18-pound koala at night, officials said Thursday.

The Australia-born koala, named Killarney, was the only one of the zoo's 11 koalas who often dared to leave her tree at night and roam the pen's ground, which apparently made her easy prey for the young male cougar that researchers call "P-22," officials said.

The big cat was seen on zoo grounds in surveillance footage during the overnight hours between March 2 and March 3. The koala was noticed missing the next morning, said John Lewis, director of Los Angeles Zoo.

"We were actually surprised that he actually came into the zoo," Lewis said. "We have security that monitors the site at night."

The zoo sits in 4,210-acre Griffith Park, part of the Santa Monica Mountains that bisect Los Angeles, and the chaparral is home to many predators, including bobcats and coyotes.

The mountain lion named P-22 was captured on surveillance footage at the Los Angeles Zoo the night that the koala went missing.

The zoo released a video and a still photo from that night that depicted P-22 on the prowl. The mountain lion wears a tracking collar, placed by biologists who have been studying P-22 in the wild since 2012.

P-22 became famous when he was photographed beneath the Hollywood sign by a camera trap. The image made the December 2013 issue of National Geographic.

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Since then, the lion has become something of a Hollywood celebrity. He even has its own Facebook and Instagram pages.

The National Park Service said it's not conclusive that P-22 killed the koala because they couldn't fully track its whereabouts that night. Biologists found a two-hour gap in the mountain lion GPS tracking data, a spokeswoman said.

"It could have been him, or it also could have been another carnivore like a bobcat, for example," said National Park Service spokeswoman Kate Kuykendall.

Mountain lions usually prey on mule deer and sometimes coyotes and raccoons, Kuykendall said.

For big cat, it's about acting naturally

"Obviously koalas are not native to this area, so it's not part of their regular habitat, but I do want to emphasize that this is not an indication of any abnormal or aggressive behavior on the part of whatever animal ate the koala bear, although it is very sad and I'm sure the public is grieving, as is the zoo family," Kuykendall said. "This is a case of a wild animal acting naturally in its native habitat."

Some koala fur was found near the zoo habitat, and the remains of Killarney, a 14-year-old female, were found 300 to 400 yards away, Lewis said.

Most of the zoo animals have since been moved into their barns and quarters at night, officials said.

The 10 other koalas were untouched the night of the attack, Lewis said.

Killarney was born in Australia and came to the zoo on May 25, 2010. At her death, she weighed between 15 and 18 pounds, Lewis said.

In January, National Park Service researchers recaptured P-22 and reported he recovered from a publicized 2014 bout with mange, believed to have been caused after he unknowingly ingested rat poison. Local media showed researchers' images of the haggard lion in 2014.

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P-22 is now about 6 years old and weighs 123 pounds, about 15 pounds heavier than his last capture in April 2014, when researchers replaced the battery in his GPS collar, the park service said.

"He's gained some weight, his tail has filled out, and he no longer has skin lesions and scabs across his body and face," Jeff Sikich, a biologist with Santa Monica Mountains National Recreation Area, said in January. "It's highly likely that he continues to be exposed to rat poison, but for now he seems to be managing."

Survived dangerous highway crossings

The lion is believed to have been born in the portion of the Santa Monica Mountains closer to the ocean, the farthest corner from downtown Los Angeles.

But to make a new home in the mountains near Griffith Park and the zoo, P-22 would have had to cross two major highways: Interstate 405 and U.S. 101, the park service said.

It would have been an adventurous crossing for the animal as Los Angeles is notorious for its round-the-clock, speeding traffic.

Beth Pratt-Bergstrom, California director of the National Wildlife Federation, said Los Angeles has "largely rallied around co-existing with P-22—and all wildlife."

"Mountain lions are called ghost cats for a reason. They are solitary animals that want to be left alone. P-22 lives in an urban park visited by millions of people and is rarely seen, demonstrating what we already know -- it is possible to peacefully coexist and the risk of danger is very low," Pratt-Bergstrom said in a statement.

P-22 and other mountain lions in and around the Santa Monica Mountains are being studied to determine how they keep surviving on the edge of the nation's second largest city, the park service said.