From the newsroom of the Washington Post.

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This is Post Reports.

I'm Martine Powers.

It's Monday, April 12th.

Today, the vast surveillance network that's helping to catch the Capitol Mob.

And the legacy of Prince Philip.

My name is Drew Harwell and I'm a tech reporter for the Washington Post.

I write a lot about surveillance technology, all the cameras and sensors and data gathering tech that shapes our lives.

And I think one of the most interesting examples of a lot of these things I write about was January 6th and the Capitol riots.

This was a huge disaster and it was even for the FBI, which is like the US's biggest most powerful law enforcement agency.

This was just a gargantuan criminal investigation for them to pursue because they had hundreds of people who busted into the Capitol.

All of whom came from across the country.

So tracking all of them down and prosecuting them for, you know, in some cases, violence for police was this massive challenge for investigators.

And so from looking through a lot of the investigative documents and a lot of the court filings as we did for this story, you know, we started to see, okay, they had a secret weapon in pursuing this investigation, which was all of these technical systems that had been gathering data on these people the whole time.

And that pretty much created this breadcrumb trail right back to people's homes and personal lives.

And what are some of the examples of the surveillance technology that they used to be able to track down some of these people?

Yeah, so they use pretty much everything and a lot of it was kind of unsophisticated stuff that we're used to, you know, social media and Facebook and kind of surveillance cameras that are just all the way wired around the Capitol, but they also use some really kind of controversial, fairly new types of technologies like facial recognition, right, where they could take an image on photo or video and have the computer tell them if they found any matches and say,

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