This photo provided by the Oklahoma County Sheriff’s Department shows Bryan Anderson. Anderson was arrested for pimping during the sweep. (AP Photo/Sue Ogrocki) WASHINGTON (AP) — Declaring child prostitution a “persistent threat” in America, the FBI said Monday that authorities had rescued 105 young people and arrested 150 alleged pimps in a three-day sweep in 76 cities. The agency said it had been monitoring Backpage.com and other websites as a prominent online marketplace for sex for sale. Backpage.com said that it was “very, very pleased” by the raids and that if the website were shut down to the advertisements, the ads would be pushed to sites that wouldn’t cooperate with law enforcement. The young people in the roundup, almost all of them girls, ranged in age from 13 to 17.