HOUSTON -- Criminals and victims pass through the Harris County Courthouse every day.

But Tuesday, one of them was just a teenager – a teenager police say became the victim of a very adult crime.

In 2006, around Hillcroft and the Southwest Freeway, the teen – then 13 years old—and three other women were arrested during a sting targeting prostitutes.

It’s prevalent in southwest Houston, and all too often the women turning tricks aren’t women at all – they’re girls.

The FBI says many of the child prostitutes are brought to Houston by pimps.

The agency tries to keep track of the pimps, even when they move from state to state.

That’s why Jason Heard was put on trial in Harris County.

He was accused of taking that 13-year-old from the Dallas area and bringing her to Houston to make him some money.

The girl, who’s now 15, testified that she also had sex with Heard.

At 4 p.m. Tuesday, a jury found him guilty and sentenced him to 20 years behind bars.

To fight the problem of child prostitution, the FBI has organized a multi-agency task force.

“HPD has given us two vice officers. They have given us officers from the juvenile division, and the Harris County Sheriff’s Office has also committed an officer,” Vanessa Walther of the FBI said.

Special Agent Walther said many of the child prostitutes no longer work the streets, but now they’re involved in organized underground networks.

“So it has made our job more difficult, and we are having to look harder and conduct more in-depth investigations,” she said.

Just this past Saturday, for example, a 13-year-old girl was arrested inside a Dallas bar for allegedly recruiting her middle school classmates to dance and sell sex there.

“One of the remarkable things that we have learned about this is that there really is a tremendous amount of money involved. There is a high demand for young girls in the prostitution world,” Lt. Ches Williams of the Dallas Police Department said.

What happens to the children involved in these crimes?

Most are provided support to get back on track.  But going from street life to the life of a typical teenager is not an easy transition.

In fact, the 15-year-old victim in the Heard case has struggled and is currently in a juvenile boot camp.