LITTLETON, Colo. -

A prank caller is suspected of launching a SWAT response in suburban Denver that locked down several schools.

The suspected "swatting" incident started when someone called 911 Wednesday to report that he had shot two co-workers and was holding hostages at a Littleton, Colorado office building. Police found no evidence of a shooting.
    
An online video purporting to show the incident show a man sitting before his computer saying "Think we're getting swatted" as SWAT officers enter the room with weapons drawn.
    
The office building is within several miles of Columbine and Arapahoe high schools, the scene of actual shootings.
    
Given their experience and training to respond quickly to mass shootings, police say they're fortunate no one was hurt.