if you searched a drop a few pounds, and take to the internet, be careful where you click. Jim avila went on the search for diet scammers. Reporter: It is a beautiful scam. Fraud with a french twist.... See More
if you searched a drop a few pounds, and take to the internet, be careful where you click. Jim avila went on the search for diet scammers. Reporter: It is a beautiful scam. Fraud with a french twist. My name is melissa theuriau -- Reporter: Melissa's so beautiful it's almost criminal. But that's as close as she comes to breaking the law. But without her knowledge, she's become the face of a massive swindle defrauding millions of desperate dieters of millions of dollars. It's just false advertising. Reporter: The trouble begins when you click one of the trillions of internet ads for weight-loss products. You're hustled off to a land of make believe, websites that look like real news organizations. News 8. Channel 9 news. Breaking news at 6:00. The sites feature photos of their trustworthy anchors, the well known logos of the biggest names in news, and that captivating investigative reporter. I mean, she's an attractive woman. Reporter: She spins a story about the hottest diet fad of the moment -- south america's acai berry diet. Amazingly, she finds success with it, losing 25 pounds in 4 weeks and reveals her findings to the world. It catches the attention of millions of consumers looking for similar results. But it also catches the eye of the federal trade commission. The bottom line is, there's nothing about the website, or the representations made on there, were true. Reporter: That's right. These news anchors? Fake. The news logos? Stolen from legitimate media outlets. And worst of all, when the pills do arrive in the mail, the fcc says you will find out that the acia berry as a miracle weight loss drug is false too. You investigated whether or not acai berry makes you lose dramatic amounts of we. Yeah. I mean, the bottom line is, it has no meaningful effect for weight loss. Reporter: The websites for for marketers looking to fatten their wallets selling you a pipe dream. 20-year-old tanner vaughn does it for a living. Reporter: What's an online marketer? What do you do? I explain it to most people as a virtual salesman. Reporter: That means vaughn will sell virtually anything for virtually anybody -- for a fee. At one time, he could sell any product to anyone. To get paid, all vaughn had to do was steer consumers to a merchant, to anyone. A lot of times, when you work at a company, they give you a list of rules. Don't break these rules. Yeah. Reporter: Do you get a book of rules? No, no. Reporter: Here's how it works -- with no rulebook to guide them, marketers like vaughn can simply sit at his computer, build a bogus news site, add a compelling, albeit fabricated, news story about a dramatic weight loss, and put it out on the internet. He's essentially trolling for desperate dieters. And when they bite and buy a product, vaughn gets paid. These guys were clearly engaged in fraud. Reporter: But before the government can stop it, the wildly successful ad featuring takes on a life of its own -- popping up all over the internet as rogue marketers cash on the face that seems to connect with consumers. Reporter: So she must be really skinny, 'cause there were a lot of websites she lost 25 pounds on. Yeah, it's pretty amazing, isn't it? Reporter: If she's not a reporter who lost 25 pounds over and over again -- who is she? To track down the mystery woman we traveled all the way to paris. It's not true. Reporter: Do you recognize the woman? Yes, I recognize her. It's me when I was young. Reporter: The one truth about melissa theuriau is that she actually happens to be a real journalist, a sensation on french television who assures us she has absolutely nothing to do with any diet pill. The scammers loved her picture, so they took it and pasted it all over their websites. Reporter: They didn't ask your permission. Never. Reporter: And they didn't give you any money for it. No, nothing. Reporter: Did you work for "consumer reports"? No. Reporter: Did you work for news 6? Remember, nobody works at any of these pseudo-news websites. There's no buildings, no staff, no cameras or reporters. Making overhead low and profits high. How lucrative can it be? It can be very lucrative, if done right. For example, some of the cases we filed, $2 million or $3 million is not unusual. Reporter: Vaughn said he started young, just 16 years old, started in his mom's house. It was never my intention to scam anybody or anything like that wlar do you mean? This wasn't true. Those two people are fake at the top. She's fake. There is nothing real on this. Did you scam people. It was a situation that I got caught up in. I did wrong. I admitted that. Reporter: Vaughn said he made good money but his earning were nothing compared to the mailbox of new jersey marketer andrew davidson began filling with fat commission. His websites, news 6 and consumer news reporter, helped generate nearly $11 million in sames, according to the government. He is capitalizing on the face from france. He should have known a genuine news organization would come calling. But when we visited him in atlantic city, things got real. Is andrew here? Yes. I am a real reporter. I want to ask you about the fake reporters on the website. Yeah, I don't have any comment. You want to talk to us at all? No. Why do you want to fake people out like that? The golf had better luck having davidson opening up, the federal trade commission sued him. Are they surprised when you go and say, this is against the law? Ky tell you, the pampbts are surprised. It's not unusual where the defendant is living in pair parents' home. The government is taking his house and his car. But don't feel too sorry. We found him cruising around in a brand new replacement. The government sued tanner vaughn, he paid nearly 80,000 and admitting wrong doing but he changed his ways blach do you say to the people who wasted their money on the plukt? I would apologize to it. Reporter: The ftc is helping people who lost cash instead of weight. This exploipds women and bhoen are suffering. Reporter: But with the huge profits at stake, the exploitations tonights today. For every website the government whacks, a new one pops up in its place. The last women in the world who needs to lose weight is shedding 25 pounds and a scammer's bank
This transcript has been automatically generated and may not be 100% accurate.