Brookfield Zoo locked down after threatening call; all staff and visitors safe after no threat found

CHICAGO (CBS) -- Brookfield Zoo was locked down and evacuated Tuesday evening, after receiving a threat to harm guests at the zoo.

Police said, around 5:15 p.m., less than an hour before the zoo was scheduled to close, a woman called a crisis hotline, threatening to harm herself and others at the zoo.

Visitors were told to shelter in place while police swept the zoo, and evacuated buildings one by one.

Police cleared the zoo by 8 p.m.

CBS 2 spoke to a woman who said her teenage son just started working at the park two days ago.

"Any parent that hears a police officer tell them there's a shelter-in-place, the first thing you think about is a gun," she said. "But, like I said, as a mom, hey, I want my kid. I want to make sure he's okay."

Police said after clearing the zoo, they learned that the woman making the threats wasn't even inside the zoo at the time.

Staff said they're looking forward to reopening on Wednesday.