The CEO of the US-based online classifieds service Backpage was arrested in Houston on Thursday, as officials said that escort advertisements on the page had "repeatedly" involved victims of human trafficking.
Nearly three dozen law enforcement officers took part in the arrest, after Carl Ferrer arrived in Texas on a plane from Amsterdam, a statement from the Texas Attorney General said.
A search was also conducted of the Dallas headquarters of Backpage, it said.
The human trafficking involved both "adult and child sex trafficking victims that had been forced into prostitution," the statement said.
"Making money off the backs of innocent human beings by allowing them to be exploited for modern-day slavery is not acceptable in Texas," the state's Attorney General Ken Paxton said.
"I intend to use every resource my office has to make sure those who profit from the exploitation and trafficking of persons are held accountable to the fullest extent of the law."
Backpage, founded in 2004, offers buyers and sellers an online platform for cars, musical instruments and antiques, but the webpage has been dogged by accusations of illegal prostitution for years.