. >> bruce carr runs a federally funded sex trafficking task force for harris county. he says it's an uphill battle where men exploit any young girl they can control. >> and it's very sad because those particular girls, a lot of times, are picked up on low self-esteem and what have you and tricked into it by these pimps, and they fall for it. next thing they know, they're wrapped into a situation they can't get out of. >> the task force regularly runs sting operations like this one to gather information from cooperating witnesses so they can painstakingly build cases one pimp at a time. >> it's tommy. i was looking to spend more time for you. >> today officers posing as johns call girls to make dates at the hotel. >> hey, girl! you free today? >> hoping to take down the men who traffic them. >> well, come on. i'm in room 106. >> investigators in unmarked cars outside notify the team that their mark has arrived. >> we've got a female en route now. her arrival could be at any time. >> the undercover posing as the john greets the girl in room 106 as uniformed officers nex