During a standard headcount last week, zoo workers noticed that Killarney, one of the zoo's 11 koalas, was missing.
After some investigation, workers found a clump of her hair near the enclosure. Approximately 300-400 yards away, they found her mauled body.
Zoo officials said P-22 was spotted on surveillance footage roaming zoo grounds the night before Killarney was killed.
"He was seen in a couple of locations, certainly would be capable of doing it," said L.A. Zoo director John Lewis.
Zoo workers said Killarney had a tendency to move down from the eucalyptus trees at night and walk around, which may have left her prone to an attack. However, P-22 wasn't recorded actually attacking the koala.
"We've looked at the GPS evidence, and of course talked to the zoo and looked at the enclosure, and it's really inconclusive," said Kate Kuykendall with the National Park Service. "He was in the area, but our GPS points are separated by two hours, so we can't say for sure."
Kuykendall said it's also possible that a bobcat or another carnivore may be the culprit.
"We're just not sure," she said.
Los Angeles City Councilman Mitch O'Farrell said regardless of P-22's role in the koala's death, the animal should be transferred from his current home of Griffith Park to a safer place "where he has adequate space to roam without the possibility of human interaction."
"P-22 is maturing, will continue to wander, and runs the risk of a fatal freeway crossing as he searches for a mate. As much as we love P-22 at Griffith Park, we know the park is not ultimately suitable for him. We should consider resettling him in the environment he needs," O'Farrell said in a statement.
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As a precaution, zoo staff are moving the other koalas, as well as other animals, from their public habitats to their indoors quarters at night.
Zoo officials also said they're looking into the possibility of building an even bigger fence around the entire zoo. The current 9-foot fence may be bolstered to 15 feet.
Officials say Killarney was 14 years old at the time of her death and she first arrived at the L.A. Zoo on May 25, 2010.