some schools sending students todd kazakiwich is live in arlington tonight. todd: the threat here at arlington high school was one of 15 called into schools around greater boston. like those other threats, this threat here at arlington high school was deemed to be unfounded. still, school administrators and police decided to evacuate the school this morning. police then brought in bomb-sniffing dogs to search the school. nothing suspicious was found, but the threat itself was quite detailed. the police chief says that' s one was made to dismiss students right away. >> the threat threatened for backpacks to explode in the school, and that any surviving students exiting the building would be shot. todd: again, after a thorough search of the building, the threat was deemed to be unfounded. school will reopen tomorrow. counselors will be on hand in case students and staff need to talk. reporting live in arlington, todd kazakiwich, wcvb newscenter ed: massachusetts wasn' t the only state targeted today. at least three schools in new hampshire and nine in northern n