HARRINGTON, Maine — A Narraguagus High School student has been arrested and charged with terrorizing for allegedly saying he planned to bring a gun to school, Washington County Sheriff Donnie Smith reported Wednesday.

Smith and several deputies were at the school Wednesday morning, and the sheriff’s office is continuing to investigate the case.

The student, who was not identified because he is a juvenile, was arrested at his home about 11 p.m. Tuesday, according to Smith. He was released into the custody of his parents with a condition that prohibits him from returning to school.

The teen is a junior at the school, according to Smith, who estimated his age at 16. Smith would not say in what community the boy lives.

“We had a threat come in to the sheriff’s office last night about a … student [who] had threatened to bring a weapon to school,” said Smith, who spoke with a reporter after emerging from the high school shortly before noon. Officers began investigating immediately, and the boy subsequently was arrested and charged with terrorism.

“It’s an ongoing investigation,” said Smith.

“What we know right now is another student overheard the threat and passed it on to the parents, and the parents passed it on to the school,” said Smith.

When pressed if the student made any threatening remarks toward students or school personnel, Smith said, “At this time, we really don’t know that … the student threatened to bring a firearm to school.”

State law defines terrorizing as communicating a “crime of violence dangerous to human life,” so that another person may be put in “reasonable fear” the crime would be committed and a building may be evacuated or secured.

The sheriff’s office was notified by the high school principal about 7 p.m. Tuesday, said Smith. He declined to elaborate on the circumstances — where and when — under which the alleged threat occurred.

School officials followed crisis plan protocols in notifying law enforcement officers “to ensure the safety of all the students,” said Smith.

“Our parents were very, very concerned,” Ronald Ramsay, superintendent of the school district that includes the high school, said Wednesday in a brief interview at the door to the school.

Ramsay said he received phone calls from about a dozen concerned parents after returning home from work Tuesday night. They expressed concern about postings they had viewed on Facebook, he said. The postings referred to “a threat of violence,” said Ramsay. “That’s as far as I’ll go.”

He quickly added that the postings were “speculation and rumor of a threat of violence.”

“As a result of some rumors and accusations floating around the Internet last night that appeared on Facebook and other modes of social media, SAD 37 in conjunction with local law enforcement took the appropriate cautionary measures to make sure that all of our students are safe,” Ramsay said in a prepared statement.

A gun was not recovered in the investigation, Smith reported.

The presence of officers at the school Wednesday was only a precaution, said Smith. One deputy remained at the school after Smith and another deputy left shortly before noon.

“We’ll be doing that for some time off and on,” said Smith.

The juvenile is scheduled to appear in court in December.

The high school is part of School Administrative District 37, which serves the towns of Harrington, Millbridge, Columbia, Columbia Falls and Addison.