Louisville Zoo gets all clear after bomb threat evacuation

11 articles · Updated · WDRB · May 1

Louisville Metro Police said around 10:22 a.m. nothing was found after about 230 people, including roughly 60 staff, were evacuated Friday morning.
The zoo began evacuating at about 9:30 a.m. and told visitors on Facebook to move to nearby Joe Creason Park while officers investigated.
Police said a bomb threat had been called in, but no device was detected and the area was declared clear after the search.

Why were multiple American zoos targeted by coordinated bomb threats last weekend?

With hoax threats paralyzing public venues, can police unmask the anonymous perpetrators?