GEOFF BENNETT: Officials in California are calling for an investigation into the actions of federal immigration officers after they allegedly injured and detained a U.S.

citizen this past weekend.

William Brangham has the latest on the growing number of Americans who are being caught up in the administration's enforcement action.

WILLIAM BRANGHAM: The incident in question took place on Saturday in Long Beach, California.

Video shows the moment Ricardo Gonzalez, a U.S.

citizen, is riding an e-bike and then is stopped alongside an unmarked ICE vehicle.

It's unclear whether the vehicle hit him or not.

He's later seen being held face down in handcuffs screaming.

RICARDO GONZALEZ, Detained By ICE: My arm is broken.

Help me.

Help me.

My arm is (EXPLETIVE DELETED) broken.

My arm is (EXPLETIVE DELETED) broken.

My arm is broken.

It (EXPLETIVE DELETED) hurts!

WILLIAM BRANGHAM: Gonzalez was later taken to the hospital and treated for serious injuries.

ICE says Gonzalez was arrested because he was rioting and damaged a government vehicle.

Details of Gonzalez's detainment come as a new investigation by ProPublica has found more than 500 U.S.

citizens have been caught up in the ongoing immigration dragnet.

For more on this, we are joined by ProPublica's Nicole Foy, who was one of the reporters on this series.

Nicole, thank you so much for being here.

Is this incident that we saw reported in California this weekend, does this align with the kinds of cases that you document in your reporting?

NICOLE FOY, ProPublica: It absolutely does, mostly because we found citizens getting detained by immigration officials for a variety of reasons around the country and sometimes in very similar situations like this, where maybe there was a protest nearby or maybe there was just an unexpected encounter between a U.S.

citizen in their neighborhood where they lived with immigration officials, who have really expanded their dragnet and the number of people that they're trying to detain.

And, sometimes, those two people co collide, quite literally in this case.

And there are many, many citizens that we have documented of the more than 500 that we found were detained so far who were also really seriously injured after their encounters as well.

WILLIAM BRANGHAM: I mean, DHS, as you reported in your series, repeatedly says that they do not detain or arrest U.S.

citizens, despite what your reporting shows.

When you say that U.S.

citizens are being detained, as you documented, who are the people that are being detained and what are the other circumstances around their cases?

NICOLE FOY: Yes, it's a mix of folks.

Sometimes, it is folks that immigration officials have accused of assaulting or interfering with immigration operations.

Sometimes, that seems to be the case.

And, other times, there is witness -- witness testimony or footage that really contradicts that narrative.

But there's also been many, many people who have been detained because of questions about their citizenship, whether they were on a construction site and didn't speak English very well, or they were -- there were questions about whether they also were here in the United States without papers.

We have seen people detained in a variety of ways.

WILLIAM BRANGHAM: What happens after these people are detained?

I mean, are formal charges filed?

It seems that if ICE then realizes you have an American citizen in custody, you would think that would be the end of it.

NICOLE FOY: Yes, some people who have been charged with -- who have been arrested on allegations of assault were charged with assault, but we found many who still to this day have not been charged with assault, even if officials release statements accusing them of that.

We also found dozens of people who were held for several days, including at least 24 hours without being able to access their phone or their lawyer or to contact their family and let them know where they were.

So it's -- some people really had a very brief detention, where it was maybe 15 minutes, 20 minutes where they're in handcuffs on the side of the road.

But other people disappeared into a system that was actually very difficult for their loved ones and their lawyers to find them, and at the same time they sometimes were seriously injured as well.

WILLIAM BRANGHAM: You shared a lot of your reporting, including the videos that you compiled, with former immigration officials to gauge their reaction.

What was it that they told you about what you had uncovered?

NICOLE FOY: They were really shocked by what they saw.

These are folks who -- two particular officials that I'm thinking of retired fairly recently.

And they said that, first of all, they had never seen this many U.S.

citizen encounters at all, let alone this level of detention, and that the -- they really characterized much of the use of force, the apparent reason or probable cause for stops, as really troubling, because it did not -- it did not seem that officers were following what they believe that they should have been trained to do.

WILLIAM BRANGHAM: Are there constitutional protections for Americans in these kinds of circumstances?

And, if so, have there been any sort of enforcement actions against officers who might have been accused of or found committing wrongdoing?

NICOLE FOY: Yes, I mean, everyone in the U.S.

has constitutional protections, whether you are an immigrant or you are a U.S.

citizen.

But what our reporting found was just, particularly when you're just looking at these detentions and arrests of U.S.

citizens, really some very troubling examples of possible violations of folks' Fourth Amendment, the right to be free from unreasonable searches and seizures, whether that's accusations of racial profiling or accusations of really excessive force use during the arrest.

But we also found hundreds of people who were arrested because they were participating in a protest.

We found many people who were also film -- were simply filming when they were arrested, and they believe that that is the reason why they are arrested.

The government may disagree, but they believe their First Amendment rights were violated in that way as well.

WILLIAM BRANGHAM: Nicole Foy of ProPublica, thank you so much for sharing your reporting with us.

NICOLE FOY: Thank you for having me.