FRESNO, Calif. (KFSN) -- Fresno Police officers say 18-year-old Edward Hannah, a former student from Central High was behind the social media post.
Once he was tracked down, Hannah told officers the threat was a joke.
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Police deemed the threat not credible but still added extra officers at the prom venue as a precaution.
Police arrested Hannah and booked him on a charge of making criminal threats.