A lion killed a young worker at a wildlife conservatory after it got loose from a locked space, the centre in North Carolina said.
Alexandra Black, 22, of New Palestine, Indiana, was killed on Sunday after being attacked by the lion in an enclosure that was being cleaned at the Conservators Centre.
The lion was shot and killed after attempts to tranquillise the animal failed, deputies said.
A "husbandry team" led by a professionally trained animal keeper was carrying out the routine cleaning when the lion somehow got loose, the centre said in a statement.
It was not clear how the lion escaped the area that was supposed to be locked, said the centre, which is closed until further notice.
"This is the worst day of my life. We've lost a person. We've lost an animal. We have lost the faith in ourselves a little today," said Mindy Stinner, the executive director of the Conservators Centre, according to WTVD-TV .
Miss Black had graduated from Indiana University in May with a degree in animal behaviour, according to her LinkedIn page.
She had been working at the conservatory for about two weeks, her family said.
"She was a beautiful young woman who had just started her career, there was a terrible accident, and we are mourning," her family said in a statement, according to news outlets.
"But, she died following her passion."
The centre said the lion was fatally shot to allow county personnel to retrieve Ms Black.
The facility was founded in 1999 and is in Burlington, about 50 miles (80 kilometres) northwest of Raleigh.
On its website, the centre said it began giving public tours in 2007 and gets more than 16,000 visitors annually.
It has more than a dozen employees and currently houses more than 80 animals and more than 21 species.
It took in 14 lions and tigers in 2004 to assist the US Department of Agriculture with caring for animals that were living in "unacceptable conditions."
Reporting by PA
