VIDEO: SWAT Team Raids Gamer in 911 Hoax

DENVER, Colo. -- Police in Colorado are searching for the 911 caller who brought SWAT teams swarming an unsuspecting video game player in a dangerous hoax called "swatting."

Online live-streaming video showed officers bursting into a Littleton, Colorado, video game company on Wednesday with guns drawn. Littleton Police Chief Doug Stephens said the threat seemed credible.

"The caller stated that he had just shot multiple people," Stephen said.

Officers thought they had an active-shooter situation, so they set up a perimeter, evacuated businesses and locked down nearby schools.

The reality of the situation quickly emerged. The people had been targeted in a disturbing prank, something often done by video gamers to get SWAT teams racing to the homes of their opponents.

It's becoming so common that Jordon Mathewson - the person victimized in Wednesday's incident - told other players he knew exactly what was happening. Fellow players watched the incident unfold on Twitch, a site where anonymous spectators can watch games played in real-time.

"It could have been any one of the thousands of people that were watching," Mathewson said. "They really like the anonymity of being online and being able to get away with stuff, and they like to test that sometimes."

The prank caller's identity is still unknown. Police are investigating and are taking the situation seriously.

"This is not a game. It's not an online game," Stephens said. "We have real guns, real bullets and there's a potential there for some tragedy."