From the Hogle Zoo facebook page:

Hi friends - We are upset, disappointed and we need your help! Last Saturday night, the Sigma Chi Fraternity from the The University of Utah purchased 150 tickets to BooLights. They purchased every available spot during that time slot.
They then drank and smashed bottles and cans in our parking lot, broke NUMEROUS Halloween decorations - punching out faces of carved re-useable pumpkins (all of which will need to be re-carved), and broke wooden fencing throughout the Zoo.
They flashed a pocketknife toward our carousel operator, forcing security to close the event one hour early - upsetting and disappointing the many other families here trying to have a fun night out.
They cost us quite a bit in damages, and lost revenue cutting the event an hour short, staff time needed for clean up and refunds.
This was unacceptable behavior and we're quite disappointed in our neighbors. We have contacted the police, the fraternity and the University of Utah.
If you see social media posts or If you were here on Saturday night and have any photos or videos of this fraternity and their dates vandalizing the Zoo and scaring our animals, staff and guests, please forward those pics along on Messenger.
Thank you!