Authorities still on edge after last year's Newtown school shooting sent Central Connecticut State University into lockdown Monday, after a man believed to have a sword and a firearm was seen walking across campus. Suddenly, the scene was frighteningly familiar, as scores of heavily armed law enforcement officials surrounded a dormitory as horns blared and terrified students huddled in their classrooms. The cause of the lockdown was a student returning to his dorm room wearing a Halloween costume, several of his friends and acquaintances told Hearst Connecticut Newspapers. [...] he was wearing the same getup -- a Samurai sword down his back and a pair of fake guns, wearing a paintball mask. If nothing else, the incident gave police and school officials a chance to test their emergency notification systems, parts of which were only recently put into place. In addition to the horns (the Whelen Outdoor Alarm System), students were also alerted by a public address message, text messages and emails, according to CCSU spokesman Mark McLaughlin. Western Connecticut State University officials, meanwhile, used their newly updated emergency campus crisis plan when they met as a group after hearing about CCSU's alert Monday. "When we heard the news, we all started wondering if we should treat this as a potential worst-case scenario," said Paul Steinmetz, Interim Associate Vice President of Institutional Advancement. Steinmetz said as part of the new emergency plan at Western, there are about 30 people besides the police department on campus with some training on how to respond to an active shooter, and other major disasters.