Late on a Monday night, driving the streets of San Jose, Costa Rica, 15-year-old Juliana agreed to talk on camera about her life as a teenage prostitute, and about the Americans who pay her about $20 for sex in cars and hotels.

Some nights she can make $100, a small fortune to a runaway.

Juliana fled an abusive home when she was only 12. When we met her, Juliana was eight months pregnant and working as a prostitute. The baby’s father is a married man, and a police officer.

Juliana’s story captures the moral and economic scope of the problem of child sexual abuse and prostitution in Costa Rica. Poverty and domestic violence drive children into the streets to sell their bodies; American tourist dollars give them economic incentive to stay there.

Costa Rica’s street scene for child prostitution is only the loose fringe of a highly organized industry derived from a booming trade in adult sex. Prostitution over the age of 18 is legal, and downtown San Jose bustles with scores of sex bars, strip clubs and escort services. Carnal tour guides, mainly Americans, meet clients at the airport and show them the ropes. There is even a barber shop where you can get a haircut and then have sex with your stylist. Small wonder then that teenagers and children have found a niche in this sex market.

In recent years, the Costa Rican government has been pressed to crack down on the institutions that peddle sex with minors. A notorious pimp, Tony “Max” Castillo, who ran a lucrative brothel with teenage girls for 18 years, was convicted and jailed, presumably shutting down the business. Castillo and his American wife, Sharon, built the thriving business in one of their San Jose homes. They flew an American flag above the property as a sign post for clients. Three years ago, child welfare advocate Bruce Harris filmed inside the Castillo brothel with a hidden camera. That tape helped to convict Tony Castillo, who is now in prison. Sharon was charged as well, but she fled Costa Rica at the time.

But the government’s conviction in this celebrated case proves to be largely superficial. Acting on a tip that the operation was still active, we called a cell phone number Tony Castillo had used for clients. We described ourselves as U.S. businessmen. A woman named Maritza questioned us at length and asked for references before agreeing to meet us.

“We have to be extra careful because the ABC show Tonight/Tonight is investigating us,” Maritza cautioned in Spanish as she sat down with us at a San Jose restaurant. Though the program’s real title had been lost in the translation, she had received a warning from Sharon Castillo, whom 20/20 investigative producer Vic Walter had located and confronted that day in Arizona.

Over beer and ceviche, Maritza detailed the Castillo operation and her own role.

Maritza says she was recruited by Sharon Castillo to work in the brothel when she was a teenager. She was lured by the promise of good money and protection. The girls lived in the house, where the tyrannical Tony would lord over them, inspect their bodies and “train” them to pleasure customers.

The ring of Maritza’s cell phone interrupted our meeting. The caller, she said, was Tony Castillo, phoning from La Reforma prison. Maritza told Tony she was convinced we were safe prospective clients and he gave her permission to proceed in arranging service for us. When we asked how it was that Tony could make and receive phone calls in prison so freely, Maritza explained, “If you have enough money in Costa Rica, you can do anything.” Tony, she said, having paid prison officials, continued to run the business from his mobile phone from confinement.

Ultimately, Maritza agreed to deliver two minors for sex. The price would be $300 each, higher than usual, she said, due to the increased risks associated with the police crackdown on underage prostitution. The girls, she said, would be 15 years old and very pretty, and we would have to pay the money directly to Maritza without ever telling the girls the price.

Maritza worked as a prostitute for Castillo for 10 years. When Tony was incarcerated and Sharon became a fugitive, Maritza became the business’ principal agent. In a way, she had climbed the ranks of the business. Now, she was the one doing the recruiting, finding young girls to bring into the life. “The Castillos,” she said, “had been very good to her.”

Shelters for recovering underage prostitutes are full of girls like those Maritza ultimately delivered to us — only to be surprised by our cameras. The combination of vulnerable children fending for themselves in Costa Rica, and thousands of American men with lots of dollars and little sympathy to spend, pierces this country’s image of prosperity.

On our last day in Costa Rica, our team decided to take up a small collection for one of the children’s shelters in San Jose. A dozen giggling girls, with bright hopeful faces gathered around us to say thanks and goodbye. Some held dolls in their hands. One carried a 8 1/2-month-old fetus in her womb. Juliana, the girl we interviewed that first Monday night, had found her way to help.

Bruce Harris is the Latin American director of the American Catholic charity group Covenant House. For years, Harris has been waging a campaign in Costa Rica to stop children from being exploited by what are known as sexual tourists. He spoke to ABCNEWS.com about Covenant House’s efforts to assist sexually exploited children in Costa Rica.

We have seen an increase in the number of complaints by street kids of sexual advances since we first raised the red flag with authorities in September 1997. Back then, we went to authorities and they brushed us off. But now, it has reached a point where anyone in the street can see what is happening. Also, the operations using teens and children are much more sophisticated.

It’s a significant issue, because it’s not just prostitution, it’s all levels of sexual abuse including incest at home. Incest is one of the “push principles” of why girls go to street. According to UNICEF, 80 percent of girls on the street have been sexually abused in their own homes. But incest is still a taboo topic.

Three years ago, the government set up an emergency phone line. It’s a 800-number kids can call but the problem is the response from the government agency that manages it — the Patronato Nacional de la Infancia [PANI], which is by law responsible for children.

When children call they should first receive emergency counseling over the phone and get a referral to a program like a shelter or counseling service. By law, the government is required to give 7 percent of all tax income go to PANI, but what we have found is that they are not giving 7 but only 4 to 6 percent. The PANI does not have enough funding to fulfill its responsibility.

Covenant House filed suit against the government for the lack of compliance with the law that guarantees that revenue for the PANI which is over 15 years old. We estimate the government owes approximately 45 million to the agency. Covenant House receives more and more calls. Our role is not to take the calls, but we help. Eighty percent of the sexual complaints filed with the country’s attorney general come from us. But the AG’s office has limited resources. For example, anytime they would like to do surveillance on a case, they borrow Covenant House’s camera. Still, today there are 360 complaints from us active in the AG’s office.

I believe teens trying to leave prostitution are not going to be able to get out of it on their own. There are a few non-governmental organizations that attend women who are victims of prostitution who are are expanding services to children and teens as well.

Still, we need to work on public opinion to help exteriorize the problem — that we will not accept sexual exploitation of children.

Is it openly discussed? This is one of the few social issues that has been maintained on the public agenda. Covenant House tries to keep the issue alive. I would say the more we talk about issue the more people become aware it should not be happening. But the more we provide mechanisms for the public to complain the more they are starting to do it.

You can learn more on the efforts carried out by Covenant House through its Web site: www.casa-alianza.org