SIOUX FALLS, S.D. -

Controversy surrounds the single largest advertiser of adult escort services on the web. The CEO of BackPage.com was arrested Thursday on felony charges related to pimping. Authorities allege that operators continued to allow criminal activity to happen on the website. This is the same website Sioux Falls Police have used to make prostitution arrests and catch human traffickers.

"BackPage (.com) is one of the different internet pages that our both detectives and officers monitor," said Officer Sam Clemens.

Not only do police monitor the site, they place their own ads.

"Once you've established that there's going to be money paid for a particular service you've really fulfilled the requirement to the law," said Clemens.

They do it in hopes of putting people like Michael Dickey behind bars. Dickey was arrested last year for trafficking his girlfriend for sex. Prosecutors say he pimped her out at several Sioux Falls hotels after setting up ads on BackPage.com. It's this kind of activity that authorities across the nation are upset about. Many say BackPage.com generates crime and turns a blind eye to the illegal activity taking place on their site.

Clemens said, "It's a little naïve for me to think that they don't know what's going on. They're still getting a fee. Their still running a business and they're looking at their bottom line."

Others say the website helps authorities catch criminals. Sioux Falls Police say they have worked with the site in the past to help them with cases. Sometimes they've been good about helping police; other times they've had issues.

"The good thing is, it makes it easier for us to try keep track of them and track of them and find people that are being forced into this," said Clemens.

Craigslist dropped it's escort ads about five years ago. If there isn't Craigslist or BackPage, police say there will always be another website and they'll always follow.

The arrest of website's CEO comes less than a week after the South Dakota joined 20 other states in filing DOCUMENTS in the United States Supreme Court in opposition to the website.