In response to what turned out to be unsubstantiated, online threats of violence at its graduation ceremony, a Massachusetts school district increased police presence at the event over the weekend. "We just had some concerns with Twitter and Facebook," Acting Police Chief Keith MacPherson said. "Sometimes people set up phony accounts and make disparaging remarks about people. ... We were concerned that it might escalate into something bigger. It was an abundance of caution to be on the safe side," MacPherson added.