Donny Pauling, Flickr

New Haven, Connecticut Police Chief Dean Esserman says they believe the phone call reporting a gunman on the Yale University campus Monday was a hoax. 

An angry Esserman says the investigation now shifts to finding the person who made the call.

Esserman says once the person is located, he will face "every charge I can imagine."  He also doesn't believe the call was made by a Yale student. 

The hoax call caused a massive and heavily armed police response to the school, and a lockdown that paralyzed the campus and traffic in downtown New Haven for hours. (Metro Network Inc)