It's a chaotic day in Santiago, Chile.

A photographer is using black-and-white film to capture a large anti-government protest and the authority's response.

He's near the center of the city when he faces a group of soldiers.

I got closer to see what was happening.

People started getting closer to the soldiers and throwing rocks at them.

The soldiers start shooting in the air.

I didn't realize that one of them had a shotgun.

I started taking photos of him.

Moments later, he's shot in the leg by pellets.

There's video of how the incident unfolded.

Chilean government rules say there must be a physical threat in order to use this type of ammunition.

But here's Palavecino Escobar with his camera.

Clearly, he's not a threat.

Here's when he's shot.... then hobbles away.

The 29-year-old says he wasn't doing anything wrong.

I never expected that a soldier would shoot at me for taking a photo.

It probably bothered him that I was taking a photo so close to him.

But this doesn't justify his action.

This is just one scene from the anti-government protests that have gripped Chile.

At least 20 people have died and hundreds injured.

Chile's security forces have been accused of misconduct and human rights violations.

We examined the police and military responses by reviewing videos and photos and talking to witnesses.

Some protesters have rioted.

But many more have been peaceful.

Early on, the president declared a state of emergency.

We are at war against a very powerful and relentless enemy who does not respect anyone or anything.

In our analysis, we saw instances of people being beaten, tear-gassed, and brutally arrested.

And one pattern: security forces shooting pellet rounds - or rubber bullets - against nonviolent crowds, like in the case of the photographer we mentioned earlier.

There's at least 400 of these pellet-related incidents, according to Chile's Human Rights Institute.

This kind of ammunition isn't intended to kill, but when fired at extremely close range, it can still cause serious or even fatal injuries.

Here's what some of them look like.

I was shot at close range.

On Oct. 22, journalists from Argentina's "Todo Noticias" were covering the protests in Santiago.

We see police being pelted by rocks and firing back at protesters.

And while on air, one of the reporters is shot by a member of Chile's national police.

Here you can see an officer taking aim.

Are you O.K.?

They just shot me with a rubber bullet.

They shot me with a rubber bullet.

That same day in Concepción, this man is out after curfew.

As the soldiers find him, the camera is rotated.

We've adjusted the footage to keep it level.

It appears he's told to stand still.

But the man continues walking towards a soldier.

A second camera then shows the soldier shooting the man in the leg at close range.

We spoke to police conduct and human rights experts, who said the man's refusal to surrender when confronted by the soldiers is grounds for arrest.

But they did not see a justification for the soldier to shoot the man.

As he is led away, a camera captures the bloody wound in his leg.

But it's not just journalists and protesters getting injured.

Back in Santiago one week later, a human rights observer was also wounded.

He was from the same group that has been documenting alleged misconduct by security forces.

And he was hit by six pellets.

The injuries were not severe.

But the fact that he was shot while wearing a bright yellow observer jacket shows that anyone at Chile's protests could be at risk.

The United Nations and other human rights groups have launched an investigation into the conduct of security forces.

Chile's president welcomed them, saying he has nothing to hide.

Hi. This is Nilo, and I'm one of the producers who worked on this investigation.

We spent weeks watching hundreds of videos on social media and connecting with sources in Chile.

The gravity of the situation hit me when we found a video showing a photographer who is shot at close range by the military.

He continued taking photos during the incident, even after he was injured.

We do this kind of work to dig into stories that are undercovered.

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