NEW BRITAIN -- 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 while horns blared and terrified students huddled in their classrooms.

But unlike last December's massacre of 20 children and six adults at Sandy Hook Elementary School and the April 2007 shooting at Virginia Tech that left 32 people dead, no one was hurt Monday in New Britain.

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. It was the same military-style costume he wore to a party a few days ago, they said.

The suspect was identified by CCSU officials as David Kyem, 21, of Newington. Kyem, a senior at the school, was charged with breach of peace and was released on $1,000 bond. He is the son of CCSU geography professor Peter Kyem.

One student suggested that David Kyem seemed self-absorbed, and may have had a poor grasp of what was going on around him.

"David walks to a different drum," said one of his acquaintances, Cole Hiney of Long Island, N.Y. "He's a nice guy, but he's really into fitness and has snake-bite piercings. Always with his headphones on."

But before Kyem's intentions and identity could be sorted out, many parents -- alerted to the campus lockdown by tweets and email messages -- converged on campus by the dozens.

They waited in a nervous throng along Paul Manafort Drive, one of several blocked-off campus access roads. They shuffled about with members of the media, who also waited for news from the authorities.

"I have a son, Jeremiah Roman, he's a senior here," said Anibal Roman, of Seymour. "He called me and he said `Dad, there's something going on -- we have to stay inside and there's a possible shooter.' So my wife and I and my daughter rushed up here. Any concerned parent would have done the same."

Ryan Goldstein, a senior from Brookfield, was doing homework in his room at James Hall, the 450-student dormitory that became the epicenter of Monday's lockdown.

It was noon and the start of a harrowing three hours for the 21-year-old Goldstein, a resident assistant at James Hall.

"I was in my room on the eighth floor at the top of the building when I heard the alarm and then the loudspeaker telling me to stay in the room, stay away from the windows and lock the doors,'' Goldstein said in a telephone interview.

"I looked out the window and saw Central police, and at that point, I went into the bathroom and shut the door and locked it," Goldstein said. "I was not aware of what was going on, but when I saw police outside, I knew it was something."

He hunkered down in the bathroom, all the while worried about the other students in the building because about half of the residents are in the dorm at that time of day, Goldstein said.

Then the police came.

"The police made their way upstairs and knocked on the door and told me to evacuate," he said. "I grabbed my phone. I didn't even take my car keys and I left. I shut the door and ran down eight flights of stairs. Then they instructed us to run as far as we could. We all ran across the campus toward Stanley Street and I went into a Dunkin' Donuts."

By then, there was a full force of university and city police officers, Goldstein said.

All the time, he said the university was sending texts, emails and voicemails to keep students updated on what was happening.

"I feel very safe on campus," Goldstein said. "The incident was responded to immediately. It goes to show that these things can happen anywhere."

Several students described Kyem as a "really nice guy," someone without evil intent. They said Kyem was probably just wearing his Halloween costume back to his room in James Hall.

"Yeah, it was the same kid we saw on Halloween," said one student, Brett, who didn't offer his last name. "And he was wearing the same getup -- a Samurai sword down his back and a pair of fake guns, wearing a paintball mask."

Another student, Anthony Brignano of Farmington, corroborated Brett's account of what may have been a huge misunderstanding. Later, several other students told the same story. They also said that Kyem -- most thought his last name was "King" -- took a city bus to get to campus.

Kyle Edwards, a freshman from Waterbury, said he was in a computer lab when his screen alerted him to the emergency.

"The computer froze with the message that there was a lockdown and to stay inside," Edwards said. "I stayed in the classroom for an hour and a half."

At about 4 p.m., CCSU administrators, the campus police chief and New Britain Police Chief James Wardwell staged an informational meeting for media and students. They said there were three "college-age" individuals taken in for questioning and none had been charged with anything.

It wasn't immediately clear why three suspects were taken away by police, and cops weren't offering much more information. One was Kyem, but his connection to the other two suspects wasn't known.

"From a personal standpoint, I can say that our prayers were answered," said Jack Miller, CCSU's president. "Certainly, there have been many other situations that didn't conclude in this way. Everybody was calm and brave, and behaved the way that they were asked to behave."

Miller praised the police "who brought this matter to a swift and safe conclusion."

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 in place. In addition to the horns, students were also alerted by a public address message, text messages and emails, according to CCSU spokesman Mark McLaughlin.

The Associated Press and staff writers Eileen FitzGerald, Linda Conner Lambeck and Frank Juliano contributed to this report.