Cop threatens to kill peaceful protestors with assault rifle in Ferguson

“I will f**ing kill you — get back!” says the officer (armed with an assault rifle), in the direction of a camera capturing the entire death threat. Asked for his name, the officer responds, “Go f### yourself.”

An officer who pointed a semi-automatic assault rifle at a Ferguson, Missouri, protester and threatened to kill him -- a tense episode caught on video and posted online -- is off the job, at least for now.

The St. Louis County Police Department announced Wednesday that a police officer from St. Ann, Missouri, "has been relieved of duty and suspended indefinitely" over the incident.

Police threatening to kill a citizen takes on special significance given what protesters are loudly, passionately demanding: charges against Ferguson Police Officer Darren Wilson for the August 9 fatal shooting of Michael Brown, an unarmed African-American teen.

The county police department laid out its version of the more recent incident, which happened shortly before midnight Tuesday. This account jibed with video later posted to YouTube.

In the video, an officer can be seen walking around with his assault rifle raised, then pointing it in the direction of protesters.

"I'm going to f--king kill you," he says. "Get back. Get back."

The St. Louis County Police described the protester involved in what it deemed "a verbal exchange" to be "peaceful."

Another man in the crowd then says out loud, "Did you threaten to kill him?"

The officer is asked for his name, to which he responds: "Go f--k yourself."

Protesters proceed to mock the officer before he's led away by another member of law enforcement.

A CNN crew also saw the officer point his weapon at those around him as he cursed, shouted and threatened people by saying he'd kill them unless they stayed away.

The St. Louis County Police said that one of its sergeants "walked over and immediately took action, forcing the officer to lower the weapon and escorting him away from the area."

"The unified command strongly feel these actions are inappropriate, and not indicative of the officers who have worked daily to keep the peace," the police department said.

The county police referred media to the St. Ann Police Department for updates on the unnamed suspended officer's status. Members of the law enforcement force charged with maintaining security have come from many communities, including St. Ann, which is just west of Ferguson.

This is not the first time unarmed protesters in Ferguson have accused police of pointing guns at them

. CNN staffers have seen some such incidents first-hand that weren't caught on tape.

Antonio French, a St. Louis city alderman who has been a fixture at the demonstrations, said he is not surprised by the video given what he's seen the past two weeks.

What is different -- in a good way, from his perspective -- is that authorities responded promptly in disciplining one of their own.

"In this case, we did see something happen to that officer immediately," French told CNN's Anderson Cooper. "And that sends a strong message that at least the folks at the top are getting it."

Neil Bruntrager -- general counsel for the St. Louis Police Officers Association, though he doesn't represent this specific accused officer -- conceded in an appearance on CNN that these kinds of things are probably happening in Ferguson, though he characterized them as "isolated incidents."

He defended the officers on the front lines of the protests, saying they have shown "admirable restraint" -- a view that's not shared by some activists -- despite being persistently egged on.

"You're asking them to stand there and stare into the faces of people who are spitting on them, who are yelling at them, who are screaming at them, ... who are touching them," Bruntrager told CNN's Erin Burnett.

"You're saying: Just take it. And ... by and large, they do."

Sometimes -- as in this particular cases, the lawyer conceded -- a police officer may act improperly. If they do, Bruntrager claimed that it is "a fatigue issue," not "a training issue," related to the psychological wear on being on the streets of Ferguson day after day.

"What happens in a situation like this is that a person is human, they respond, and that's what you saw (on the video)," Bruntrager said. "It's unfortunate, it's unpleasant, but it's a human response."

The man in charge of maintaining security in Ferguson, Missouri State Highway Patrol Capt. Ron Johnson, considers this officer's actions an affront to all those who have doing things the right way.

Talking to CNN's Don Lemon about the video, Johnson said, "I was disturbed by it, I was bothered by it, and I was disrespected by it."