The FBI operated 23 child pornography websites on the dark web to identify users with malware, according to an affidavit obtained by the American Civil Liberties Union.

It was previously known that the agency maintained the child porn website Playpen to help law enforcement identify its users. Now, as Ars Technica reports, the FBI had not disclosed that it also operated 23 other sites “dedicated to the advertisement of child pornography, the discussion of matters pertinent to child sexual abuse, including methods and tactics offenders used to abuse children, as well as methods and tactics offenders used to avoid law enforcement detection while perpetuating online child sexual exploitation crimes.”

The documents explain that the websites were in the “normal course of the operation of a website” and that “Websites 1-23 operate at a government facility, such request data associated with a user's actions on Websites 1-23 will be collected.”

Sources point to FBI office in New York City for Hillary Clinton leaks Show all 8 1 /8 Sources point to FBI office in New York City for Hillary Clinton leaks Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÃs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÕs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÕs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÕs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÕs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÃs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÃs private email server. (Photo by Drew Angerer/Getty Images) Getty Sources point to FBI office in New York City for Hillary Clinton leaks NEW YORK, NY - NOVEMBER 4: A view of the Jacob K. Javits Federal Building, where the Federal Bureau of Investigation (FBI) has a field office on the 23rd floor, November 4, 2016 in New York City. FBI Director James Comey informed Congress last Friday that his agency was taking steps to review newly discovered emails relating to Democratic presidential candidate Hillary ClintonÃs private email server. (Photo by Drew Angerer/Getty Images) Getty

Fred Jennings, a cybercrime lawyer, told the news outlet that while the paragraph doesn’t quite say the FBI operates the websites, there’s no other way to interpret that 23 websites are hosted at the government facility, with their and to their benefit. He added that it's "clever phrasing on their part.”