Fans were enjoying a Rascal Flatts concert in Indianapolis, but were left confused when the music stopped.
The group abruptly left the stage, and didn't return for their encore.
Staff quickly evacuated the amphitheater, and officials say it's an ongoing investigation.
The next video shows the moments right before the band left the stage.
Fans were disappointed, but also understanding, with one concert-goer saying she saw 'a man taken down in handcuffs.'