"The notion that we're going to criminalize conduct that is First Amendment activity is troubling, and I think it was troubling to the jury," Nelson said.
Kevin Beck, the prosecutor for Little Canada, said that he was disappointed by the verdict but that the case was worth prosecuting.
Beck said that Henderson got within three feet of a paramedic trying to do a medical assessment of the drunken man and that Henderson continued recording after the paramedic asked him to stop.
Beck said the paramedic had to ask a sheriff's deputy to talk to Henderson, which delayed the ambulance crew in getting the drunken man to a hospital.
"The crime was committed when the paramedic had to stop providing medical care" to try to get Henderson to stop taping, Beck said.
But Henderson testified that the paramedic didn't tell him to stop recording, and his lawyer argued that Henderson didn't interfere with the drunken man's care.
Henderson was 35 feet away "quietly" taping while the drunken man was being questioned by the ambulance crew and frisked by police, defense attorney Kevin Riach said.
Henderson, a welder, is a "meek, mild-mannered guy" whose hobby is videotaping police to keep them accountable, Riach said.
Henderson said he doesn't have animus toward police and he's never suffered from police abuse. But he said he got interested in videotaping police activities after an August 2012 incident in which a YouTube video showed a St. Paul police officer kicking a man named Eric Hightower during an arrest.
When Henderson taped the ambulance crew and Ramsey County sheriff's deputies in Little Canada, he was doing what half the TV news crews in the metro area do every day, Riach said in closing arguments.
But Riach said when a sheriff's deputy, Jacqueline Muellner, asked Henderson what he was doing and he refused to give her his name, that angered her and she snatched his camera.
That led to "the mystery of the disappearing video," Riach said.
Riach said testimony from Muellner showed that the camera was temporarily left in Muellner's squad car and in her office mailbox, and was not adequately secured by police.
"That camera should've been put into evidence right away," he said. "We'll never know exactly what happened to it."
Riach also said prosecutors failed to prove the charge that Henderson intended to obstruct the ambulance crew, and he never physically got in the way of the emergency responders.
"He was sitting peacefully off to the side, videotaping," Riach said.
But Beck said that when the paramedic asked Henderson to stop taping, he knew his behavior was offensive and obstructive.
Beck said Henderson didn't have to physically get in the way of the ambulance crew to be guilty of the misdemeanor. If his actions had the effect of obstructing the ambulance crew, he committed a crime, Beck said.
Joshua Norgaard, the Allina Health Emergency Medical Services paramedic who was on the ambulance call that night, testified that he asked Henderson to stop taping to protect the privacy of the drunken man.
Henderson said he could have resolved the case by accepting a prosecution offer to plead guilty to a petty misdemeanor and pay a $50 fine.
But Henderson insisted on a trial.
"It's the principle of it," Henderson said. "It's our First Amendment right to film law enforcement personnel."
Henderson said he would have represented himself at trial if he hadn't received free legal help.
"Andrew is a unique guy in which he was willing to stand up and fight on this," Nelson said. "I think we should admire him."