Carl Ferrer, chief executive of the advertising website Backpage.com, was arrested on Thursday on criminal charges including pimping, as authorities investigate the company, which has been accused of facilitating sex trafficking of minors.

The attorneys general of Texas and California said in a statement that Ferrer had been taken into custody in Houston on a California warrant.

Backpage, the second-largest U.S. online classified ad service after Craigslist, has faced scrutiny from the U.S. Senate as well as civil lawsuits over allegations that the site facilitates sex trafficking, especially of children.