A high school student from Andover was arrested last night, accused of posting a picture of assault rifles on Snapchat along with a warning to fellow students not to come to school today, authorities said.“The alleged origin of the social media posts was traced to an Andover High School junior, and police went to his home to question him,” a press release from Andover Public School Superintendent Sheldon Berman stated.Police said the photo of assault rifles posted on Snapchat was downloaded from the internet.