KINGSTON, R.I. (CBS) – Was it a campus game that led to a lockdown at the University of Rhode Island? Possibly. The University of Rhode Island’s main campus in Kingston was on high alert until Thursday afternoon, hours after a report of a possible gunman in a lecture hall.

In a news conference, State Police said no gun was found after a room to room search of the building and that there was no gunman.

The scare started around 11:30 a.m. when campus police received a call saying there was a person with a gun on campus in Chafee Hall.

The university’s website crashed due to the high volume of people looking for information.

On its Facebook page, URI instructed students to “secure yourself indoors, stay there, and do not move about outside until further notice.”

A student who was recording a lecture in Chafee Hall captured the moment that started the lockdown. A man is heard on the recording saying “I’m a nice guy. I’m a nice guy.” That prompted yelling and screaming. The professor told everyone to leave the building and people starting running outside.

URI Freshman Ahnise Kassab found himself in the middle of the chaos. “I was just taking notes and I heard somebody shrieking making a really loud noise,” he says. “I just saw a bunch of people get up and start running and somebody yelled, ‘He has a gun, He has a gun.’ And I just ran out right to the nearest exit and sprinted out as fast as I could.”

Kassab describes the scene in the moments after the supposed gunman was spotted: “It was really chaotic. A lot of people were just standing still, so as I was running away, I told everybody, ‘Run! Run!’ Because obviously in my mind I’m thinking there’s some crazy guy with a gun and I just wanted to make sure everybody was all right.”

State police said they found a Nerf gun in a backpack during their search of the lecture hall, but it belonged to a student in the classroom. Investigators are not sure if it’s connected to the incident.

Ryan Cabral, president of URI’s Humans vs. Zombies club, told WPRI.com Nerf guns are used in a well-known game played at the school that he described as an “extreme version of tag.”

“We know about the game,” said campus police Major Stephan Baker, “but we haven’t had any problems in the two or three years it’s been played.”

Still, they don’t know if the incident was part of the game, or if the person who said it was serious. No weapon has been found, and the campus is back to normal.

WBZ-TV’s Bill Shields and Jim Armstrong contributed to this report.