Detectives say Nathan Myres, 17, intended to carry out the threat on April 20.
Cops arrested a 17-year-old man who allegedly said he was going to conduct a Columbine-type shooting at a Long Island high school.
Students told detectives that Nathan Myres pledged to carry out the threat at the Plainedge High School in Massapequa on April 20 -- the 11th anniversary of the day that two Columbine students murdered 12 students and one teacher before killing themselves.
Myres was taken into custody without incident late yesterday afternoon. He had been a pupil at Plainedge High School until earlier this year, when he transferred to a special needs program.
Nassau County police say they began investigating several days after a rumor began rippling through the school that an ex-pupil was planning an attack.
Police haven't found any weapons and it is possible the teen was just trying to scare people, Detective Lt. Kevin Smith said.
But, he added, "Teenagers have to understand that in this day and age, they can't make these type of threats.''
Myres remained in custody Saturday after his arraignment on charges of making a terroristic threat -- a felony. His bail was set at $25,0000. It was unclear when he would get a permanent lawyer.
Myres doesn't live with his parents, police said. His mother is dead and his father lives in another state.