Foreign student threatened to shoot up a Catholic school - here's the arsenal cops found

Police say that a foreign exchange student was prevented from shooting up his high school after they were tipped off by his friend about his plans.

Here's what happened

18-year-old foreign exchange student An Tso Sun told a fellow student who was 17 years old not to come to their school on May 1 because he was going to attack the other students. That classmate spoke to school authorities about the threat, and they contacted the police.

Sun was arrested later by the police, and said that he was joking when he warned his classmate at Bonner and Prendergast Catholic High School.

Police say they discovered 16,000 rounds of ammunition and a handgun in a black carryall case and they allege that these belong to Sun, but have not revealed how they discovered the evidence.

Sun is originally from Taiwan.

The social media account for the Upper Darby police tweeted the booking photo for Sun.

"An Tso Sun, 18, arrested for threatening to shoot up local high school," they tweeted.

"Sun was found to have a military vest and ammunition at his residence," they added. "Kudos to the person who stepped forward and helped to avert a tragedy."

“We have zero tolerance for anyone who threatens to shoot, bomb, or hurt a school," said Upper Darby Police Superintendent Michael Chitwood. "They will be locked up. Period.”

Sun denies the charges

Lawyers for Tso Sun released a statement denying the allegations and asserting rhetoric was growing overheated in the media about the case.

“Our client just turned 18 in January and is a senior in high school," the statement said. "This young man has had no prior contacts with the courts and has been considered an affable, precocious student with no discipline or antisocial tendencies. The young man’s parents have flown in from Taiwan and fully support their child."

"Our investigation reveals that there was no intention to terrorize or otherwise commit any criminal act," they added. "The family is concerned by the rising level of rhetoric that is being transmitted to the news media and hopes that the public will keep an open mind as all the facts and circumstances are brought forward.”

Here's a media briefing with Upper Darby official Chitwood: