What's not seen is what happened just after he stopped recording: Demint says three officers tackled him, took away his smartphone and then tried, unsuccessfully, to erase the video. They then arrested him on charges of obstruction of governmental administration and resisting arrest.

"I am 100 percent innocent," the 20-year-old Long Island college student told reporters earlier this month. "I didn't do anything wrong. I was just there to videotape."

Civil liberties experts say Demint is part of a growing trend of citizen videographers getting arrested after trying to record police behavior.

It's a backlash that comes as smartphones have made it easier than ever to make such recordings, which have become key evidence in high-profile cases of alleged excessive force, including the shooting of a fleeing suspect by an officer in South Carolina, the dragging of a Baltimore man into a police van, and the chokehold death of a New York City man on a Staten Island sidewalk.