Police have discovered more than 1,600 rounds of ammunition and a handgun allegedly belonging to an 18-year-old foreign exchange student charged last week with threatening to "shoot up" a Roman Catholic high school in Drexel Hill.

The host parent, a lawyer who has not been identified, went to An Tso Sun's bedroom at her home in Lansdowne and removed a 9mm Glock handgun and ammunition before police arrived to conduct a search, Superintendent Michael Chitwood of the Upper Darby Police Department said Monday night.

"She immediately went to the bedroom" after she was contacted by Bonner and Prendergast Catholic High School that Sun had made the threat to another student on March 26, Chitwood said.

Citing the ongoing investigation, Chitwood on Monday declined to say how or where police found the gun and ammunition, except that they were inside a black carryall case. The 1,600 rounds included ammunition for the Glock as well as ammunition for an AK-47, an AR-15, and a shotgun.

Sun had sent a video to fellow classmates of himself in his bedroom showing off the Glock, Chitwood said.

Sun remains charged with one misdemeanor count of making terroristic threats. His host parent has not been charged.

The Taiwanese national was being held on a detainer lodged by U.S. Immigration and Customs Enforcement. That means he cannot be freed on bail, which had been set at $100,000, Chitwood said.

Upper Darby detectives are set to meet Tuesday with the U.S. Department of Homeland Security.

Sun's parents, identified by the Associated Press as the actor and assistant film director Sun Peng and the actress Ying Di, arrived Friday from Taiwan and have obtained a new legal team for him.

Attorneys Robert C. Keller and Michael N. Kotik said in a statement Monday evening: "Our client just turned 18 in January and is a senior in high school. 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. 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."

Sun allegedly warned a 17-year-old  male classmate last week not to come to school on May 1, saying he planned go on a shooting spree that day, police said. The classmate reported the statement to a school employee and the school notified Upper Darby police at 9:38 a.m. Tuesday.

Sun was arrested at the high school that day after voluntarily speaking with a detective.

He told police that he was kidding about the threat and had told the classmate that he was "just joking."

Officers executing a search warrant in Sun's bedroom Tuesday night found a military-style ballistic vest, crossbow with scope and light, 20 rounds of 9mm ammunition, military ski mask, ammunition clip loader, a strangulation apparatus known as a garrote, and other equipment.

No firearm was found during that search.

Chitwood said Sun used a school-issued iPad to search for how to obtain parts to assemble a functioning AK-47 or AR-15 semiautomatic rifle.

Sun obtained parts online to assemble the functioning Glock. Chitwood noted that Sun, by using this method, was able to circumvent Pennsylvania's age limit of 21 for buying a handgun.

Sun's previous attorney, Enrique A. Latoison, said last week that the exchange student has the equipment found in the original search of his bedroom because he was interested in a law-enforcement career and was planning to major in criminal justice at a university.