CHICAGO (CBS) — Law enforcement officials calls it the world’s top online brothel.

The government seizes and shuts down Backpage.com, the classified ad site, best known for selling sex.

The move is celebrated by Cook County Sheriff Tom Dart.

“This is huge, This site has been the primary focal point of sex traffickers. It’s a victory for victims everywhere.”

CBS 2’s Audrina Bigos explains what this means.

For a long time lawmakers and advocacy groups have called for an investigation into Backpage.com.

Late Friday, the federal government sealed the website.

But the details are still sealed by the court.

It’s an online classifieds site selling everything from phones to furniture.

Best known for selling sex.

Not anymore.

An alert on the site saying “backpage.com and affiliated websites have been seized as part of an enforcement action.” 

The Justice Department shutting it down over sex trafficking ads.

“I honestly never thought I would see this day because literally for a decade now we have been fighting this battle,” says Cook County Sheriff Tom Dart.

Dart has waged a war against websites like backpage.com that he says have facilitated prostitution and sex trafficking of minors.

His department has made hundreds of arrests.

“We’re now going to have to see where these traffickers are going to go. Because we know they’re not going to go away,” says Dart.

Last year, a Chicago Police Commander talked to CBS News’ Anna Werner about his vice unit posting phony ads to catch people hiring prostitutes.

When asked how long it takes to get responses, the commander said “within a minute or two.”

Last fall, Yvonne Ambrose, a Chicago mother, testified before the U.S. Senate.

She told lawmakers her 16-year-old daughter Desiree Robinson was prostituted on Backpage.

The man who found her on Christmas Eve in 2016 beat and choked her before cutting her throat.

“Backpage.com and other companies like this must be held responsible for what they’ve created,” says Ambrose.

This week Charles McFee pleaded guilty, admitting he introduced Robinson to a pimp for a finder’s fee of $250.

Last year, a senate report alleged Backpage.com “knowingly concealed evidence” of child sex trafficking.

Backpage executives were called to testify but took the fifth.

There have been previous cases against Backpage that were thrown out.