Sex Tourism: ABC News Goes Undercover

April 5, 2010— -- Federal law enforcement sources tell ABC News that the FBI and customs officials are investigating allegations that some fishing and hunting tour businesses are arranging sex with children for American men overseas.

ABC News wanted to know what tour operators offer and whether they market an illegal sex trade?

Wearing hidden cameras, we entered a convention, sponsored by the Dallas Safari Club, where tour companies sell top-dollar hunting and fishing trips all over the world -- some with promises of great parties and beautiful women.

"I mean, it's a third world country and you can do whatever you want," one tour operator told us. "You know if you want to do a party it's not like here—you can't touch, you can't look—you can do whatever the f**k you want."

Said another, "It will start off with six [young women], then it will be twelve, and then it'll be eighteen and then you guys will be just retreating. I'm serious."

But we've heard it's not just women on offer; it's also young girls.

We found one operator who, after at first refusing, tells us when we catch up with him the following day that he can make it happen.

"We'll float the idea to my guy that's going to take care of this thing for you and he can get it done," he says. "I know…he can get that done. But it's probably going to be…it's going to have to be real stealthy…in other words, I don't know…and I'm not saying anything but something is going to happen."

Federal investigators are looking into possible child sex abuse on tours from Central and South America to Africa.

Phil Marsteller, who operates fishing tours in Brazil, says abusing minors has become a cancer on his industry.

"What better way to get away from your wife and go be the -- you know, have the Jekyll and Hyde personality and go do something else than going on a fishing trip to the Amazon that's viewed as family friendly," he said.

The offenders aren't who you might expect. "You're talking about business people, doctors, lawyers, politicians," says Marsteller. "You know, people with lots of money."

Marsteller has gathered pictures and video of what he says are underage Amazonian Indian girls cavorting with American men on board a competitor's boat.

Brazilian authorities are looking into those allegations and have obtained affidavits from Amazonian Indian girls as young as 13 who say that employees for an American fishing tour operator came to their villages and offered them cleaning jobs, which they accepted because they needed the money.

Once on the boat, however, they say they were forced to pose in nude pictures and have sex.

We met two girls who told us they were given string bikinis and cocaine – and then expected to have sex.

"I was forced to have relations with one of them," says one girl, who was 16 at the time.

In a sworn affidavit, another girl, who was just 13 at the time, says she was impregnated by an American whose name she didn't even know -- and that afterwards her family threw her out.

That tour operator and Marstellar competitor says it's all lies.

But listen to what the tour operator we spoke to on hidden camera in Dallas -- the one who said he could introduce us to someone who would arrange for us to meet underage girls had to say about Marsteller.

"There's a code of the West in this industry that nobody breaks -- and he broke it. That's why nobody likes him."

When ABC News later contacted that tour operator, he insisted he never had arranged for clients to meet young girls and would never have followed through on his offer to help provide them.