Police have arrested a 16-year-old Brooklyn highschool student for threatening to kill three people - a teacher,another student and a McDonald's employee. The boy was arrested on charges of making terroristic threatsand aggravated harassment. He has not been identified by name. Police say a teacher at James Madison High School spotted a noteWednesday on a desk shared by the student and two peers. Theteacher then contacted security officers. Classes were unaffected and school officials did not evacuate orlock down the school.