Backpage.com CEO Carl Ferrer (center) leaves a hearing of the Senate Homeland Security and Governmental Affairs Permanent Subcommittee on Investigations on Jan. 10, 2017 after invoking the Fifth Amendment. (AP photo)

(CNSNews.com) -- Backpage.com closed down its controversial adult classified ad section in the U.S. on Monday, claiming it was a victim of government censorship.

The shut-down occurred the same day the Senate Homeland Security and Governmental Affairs Permanent Subcommittee on Investigations released a joint staff report that accused the company of knowingly sanitizing online ads by deleting “code words” such as “innocent”, “cheerleader”, and “amber alert” to conceal child sex trafficking.

Backpage.com has insisted in court and elsewhere that its activities are protected by the First Amendment and Section 230 of the Communications Decency Act (CDA), arguing that it was merely acting as a “conduit” for third-party content.

But the Senate report pointed out that the Ninth U.S. Court of Appeals ruled in 2008 that immunity granted under the CDA does not apply in cases where a website operator “edits in a manner that contributes to the alleged illegality.”

“Backpage has maintained a practice of altering ads before publication by deleting words, phrases, and images indicative of criminality, including child sex trafficking,” the Senate report stated. “Backpage has avoided revealing this information….

“Backpage had good reason to conceal its editing practices,” the report continued. “Those practices served to sanitize the content of innumerable advertisements for illegal transactions – even as Backpage represented to the public and the courts that it merely hosted content others had created.”

The report was the result of the subcommittee’s 20-month investigation of Backpage, which was the subject of “the first civil contempt action authorized by the Senate in more than 20 years”.

It was based on interviews with employees and subpoenaed internal documents that showed the company used an automated “Strip Term From Ad filter to strip scores of words indicative of prostitution from ads before publication.”

“When a user submitted an adult ad containing one of the above forbidden words, Backpage’s filter would immediately delete the discrete word and the remainder of the ad would be published after moderator review,” the report explained.

“Of course, the Strip Term From Ad filter changed nothing about the real age of the person being sold for sex or the real nature of the advertised transaction. But as [Backpage COO Andrew] Padilla explained, thanks to the filter, Backpage’s adult ads looked ‘cleaner than ever’.”

Subcommittee Chairman Rob Portman (R-OH) dismissed Backpage’s claim of censorship, stating: “That’s not censorship. That’s validation of our findings,” during a hearing Tuesday on Capitol Hill attended by five of Backpage’s co-founders and top executives.

Portman added that he and Ranking Member Claire McCaskill (D-MO) “both went to law school and we don’t remember learning that covering up crimes is protected speech.”

Backpage.com CEO Carl Ferrer, COO Andrew Padilla, general counsel Elizabeth McDougall, and co-founders Michael Lacey and James Larkin all pleaded the Fifth Amendment when Portman and McCaskill tried to question them about the use of the filter to edit “code words” for underage minors out of the ads they published.

“If an underage girl is being sold for sex on Backpage and her pimp puts the word ‘Lolita’ in the advertisement, stripping that term out of the ad doesn’t magically change the girl’s age, does it?” Portman asked Ferrer.

“After consultation with counsel, I decline to answer your question based on the rights provided by the First and Fifth Amendments,” Ferrer responded, refusing to answer any more questions from Portman or McCaskill.

All of the other Backpage executives and co-founders also pleaded the Fifth.

In his opening statement, Portman noted that “the National Center for Missing and Exploited Children reported an 846% increase in reports of suspected child sex trafficking from 2010 to 2015 – a spike the organization found to be ‘directly correlated to the increased use of the Internet to sell children for sex’.”

“NMEC tells us that Backpage is linked to nearly three quarters (73%) of all suspected child sex trafficking reports that it receives from the general public through its ‘CyberTipline’,” Portman added.

“And according to a leading anti-trafficking organization called Shared Hope International, ‘[s]ervice providers working with child sex trafficking victims have reported that between 80% and 100% of their clients have been bought and sold on Backpage.com.”

McCaskill, who noted that that the report was a bipartisan effort that “is not a common thing these days in the U.S. Senate,” said in her opening remarks that “Backpage is a $600 million company built on selling sex, including sex with children. And the company knows it.

“They did not turn away ads selling children,” she pointed out. “They just tried to make it less obvious and, worse, coached traffickers and pimps on how to clean up their ads” to avoid law enforcement.

“This investigation is not about curbing First Amendment rights of online platforms for speech – rights which are more important now than ever – or using the powers of the Subcommittee to target private actors engaged in unpopular conduct,” McCaskill continued. “This investigation is about understanding how criminals systematically use online platforms to transform normal American teenagers into sex slaves.”

The subcommittee hearing also featured emotional testimony from several parents of trafficked teenagers, including one tearful mother whose 15-year-old daughter was “repeatedly raped, beaten, threatened and treated as a sex object every day” while being advertised on Backpage as a “weekend special”.

She told subcommittee members that “we finally got Natalie [not her real name] back… but our Natalie was gone. Our new American Dream is to live in an America that doesn’t stand aside when little girls are sold online as commodities.”

Another mother testified that Backpage refused to remove nude and sexually explicit photos of her then-underaged daughter despite her “numerous” pleas to do so.

“We are still in the process of healing eight years later,” she told the subcommittee. “My daughter struggles with it even now on a daily basis.”

Pointing out that “every child is vulnerable at one point or another,” she warned other parents about the dangers of online predators.

“Every kid has access to this evil, and this evil has access to them,” she said.