Lur killed a young worker at the Wildlife Conservatory on Sunday after being released from locked premises.
Alexandra Black, 22, from New Palestine, Indiana, was killed on Sunday after her lover hit the enclosed area that was cleansed at the Conservatory Center, according to a statement by the Sheriff's District Office.
The lion was shot and killed after trying to calm the animal, MPs said.
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The "Animal Breeding Team" led by a professionally trained animal guardian routinely cleaned when the lion somehow freed, the statement said.
It was not clear how the lion fled from the area that had to be locked, the center said, which was closed for further.
– This is the worst day in my life. We lost a person. We lost the animal. Today we have lost a bit of faith in ourselves, "says Mindy Stinner, Executive Director of the Conservatory Center, according to WTVD-TV.
Black graduated from the University of Indiana in May with an animal behavior diploma, according to her LinkedIn site. She has been in the conservatory for about two weeks, her family said.
"She was a beautiful young woman who just started her career, a terrible accident happened and we are sorry," says Black's statement. "But she died after her passion."
The center said the lion was deadly hit to allow county staff to retreat to Black.
The facility was founded in 1999 and is located in Burlington, about 50 miles (80 kilometers) northwest of Raleigh.
On its website, the center announced that it started public tours in 2007 and has more than 16,000 visitors annually. It has more than a dozen workers and currently has more than 80 animals and more than 21 species.
The center says that in 2004, 14 lions and tigers needed to help the US Ministry of Agriculture to take care of animals living in "unacceptable conditions".