LaGuardia HS ‘shoot’ posting

A student at Manhattan’s famed LaGuardia HS threatened to shoot up the performing-arts school in a disturbing Instagram post, police said Friday.

Bennett Lin, 17, a senior, was arrested at his home Friday morning after posting a “polling’’ question at about 10:45 p.m. Thursday asking if he “should shoot up the whole school tomorrow.”

People who saw the message alerted cops, who then flocked to the renowned school — known for its star-studded alumni — and deemed it safe Friday. There was no evacuation. Lin, of Queens, was arraigned Friday and issued a desk-appearance ticket for aggravated harassment.