A Radnor high school student who allegedly tried to "shake down" another student for lunch money was arrested after he told police he had a handgun and had stashed it in the high school, officials said today.

The school remained open and will open at the regular time tomorrow morning, but with increased security, said spokeswoman Lisa Williamson.

The 16-year-old student, who was charged with a long list of offenses, including making terroristic threats and illegal possession of a weapon, was taken to the Delaware County juvenile facility, where he remains in custody, said Radnor Police Lt. Joe Lunger.

Lunger said that the student was charged as a juvenile and that his name would not be released. He said the initial altercation appeared to be a case of "one student" - the one who was arrested - "shaking down another kid for lunch money."

School officials called police after the two students were seen fighting in the high school at about 9 a.m. The 16-year-old, after being taken to the Radnor police station, told police that he had been carrying a concealed weapon, Williamson said. The student told police that he had hidden the gun in an administrator's office at the high school after he was taken to the office for fighting, she added. The police found the handgun in the office, Williamson said; no one had seen or been threatened with the gun at the school, she added.

Lunger said that it does not appear that the gun, a small-caliber weapon, was taken from the student's home, but police did not know how he obtained it. The gun was not loaded when police found it, he said, but ammunition was found with it.

This is the second gun scare this school year at Radnor High School, a high-performing school in a prosperous district. The high school was shaken in October when a senior, Cameron Plaice, was arrested for writing a gun threat on a bathroom wall.

Plaice, who spent 12 days in the Delaware County prison after he was arrested, was eventually allowed to enter a first-time offender's program; he is finishing out the school year at a school in Chester County. Plaice told officials he never intended to hurt anyone and was responding to anti-Semitic and racist slurs he had seen on the wall.

Contact staff writer Dan Hardy at 610-701-7638 or dhardy@phillynews.com.