Sex ads platform Backpage.com was seized by the Federal Bureau of Investigation Friday hours after its founder's Phoenix home was raided.
Visitors to the site landed on a notice from the federal government announcing its seizure.
"Backpage.com and affiliated websites have been seized as part of an enforcement action by the Federal Bureau of Investigation, the U.S. Postal Inspection Service, and the Internal Revenue Service Criminal Investigation Division, with analytical assistance from the Joint Regional Intelligence Center," the announcement read.
Founder Michael Lacey's Sedona home was raided by the FBI Friday morning, Evan Wyloge, of the Arizona Center for Investigative Reporting, tweeted. He said Lacey's neighbors witnessed the raid, reporting that "about 20 undercover cops" swarmed the property.
Phoenix FBI told The New York Daily News that "law enforcement activity is occurring."
The U.S. Department of Justice did not immediately respond to a request for comment.
Other agencies were also involved in the enforcement action, with more information forthcoming, the FBI said.
The Stop Enabling Sex Traffickers Act, known as SESTA, passed both houses of Congress last month as part of a push to crack down on Backpage.com and other sites accused of facilitating human trafficking.
It awaits President Donald Trump's signature.
Some sex workers argued that the legislation hamstrings their ability to safely earn a living.
