BROOKE GLADSTONE: This is On the Media. I'm Brooke Gladstone.

BOB GARFIELD: And I'm Bob Garfield. It's not every day you're asked to safeguard and share the fortunes of a millionaire who died without heirs. Oh, wait. Yes it is, if you have an e-mail account, in which case you almost certainly have constant encounters with the notorious Nigerian 419 fraud. It's estimated that the scam, which asks for a gullible recipient's bank account number in exchange for promised millions, is the third largest industry in Nigeria, and its perpetrators exist in a kind of legal netherworld not worth the price of international policing and protected by Nigeria's culture of corruption. Targets of the 419 scam, named for Section 419 in the Nigerian criminal code, have formed vigilante groups with names like "Artists Against 419," and are taking the law into their own hands, mobilizing victims around the world to strike back. Josh Rosenblum wrote about these online avengers for Legal Affairs magazine, and he explained how the scam works.

JOSH ROSENBLUM: The basic premise of the scam is that there's some hidden cache of money. Now, it might be lottery winnings, it might be an estate where the owner of that estate has died without any heirs, and it can be yours, if only you're willing to front some money to help with things like bribing officials or paying taxes or somehow greasing the wheels that's going to get the money in your hands.

BOB GARFIELD: Tell me how many people are suckered into this kind of deal and how much money they're losing.

JOSH ROSENBLUM: It's very difficult to get an exact number because many people are ashamed of coming forward once they've been taken in by a scam. The Internet Crime Complaint Center has registered every year since 2000, a 50 percent increase in the complaints reported to it. That's over 200,000 complaints in 2004 alone. Obviously not all of those are of the Nigerian scam variety, but a portion of them are, and it keeps growing. This scam is estimated by the Secret Service and by other governments to pull in hundreds of millions of dollars a year.

BOB GARFIELD: Well, how in the world could anybody fall for so transparent, you know, a gambit?

JOSH ROSENBLUM: That's a great question, and there are different explanations, depending on who you ask. I think the most common explanation is greed. People want to believe that they're getting something for nothing.

BOB GARFIELD: Okay. Now, I know that if I sent some sort of illegal communication, a death threat or some such thing, that I could be traced through my Internet service provider to, I guess, my very own IP address and eventually, you know, tracked down, like they do with hackers and other criminals. Why can't the cops get close to the Nigerian scammers?

JOSH ROSENBLUM: Well, there are several reasons for that. One just has to do with the fact that this is an international crime, and the host country for many of these scammers, Nigeria, the law enforcement does not function as effectively as it does in the States or in Western Europe, so even if they were able to identify the perpetrator, it's unlikely that law enforcement would actually go after them. The second reason may be that a lot of times these perpetrators will take over another computer and use that computer to send out the e-mails. And so the person who's actually sending the e-mail may be an innocent who's sending that e-mail unawares.

BOB GARFIELD: So, frustrated by the inability of law enforcement and the Nigerian government to crack down [LAUGHS], various victims and near victims have taken the law into their own hands. How have they done that?

JOSH ROSENBLUM: Some of them are, you know, your prototypical geek, IT folks. Some of them are retired professors, retired doctors, retired lawyers who have time on their hands. And what these organizations have done is that they've made it extremely simple for anybody without a great deal of technical knowledge to take down these websites. The basic idea here is to waste the scammer's time. So you reply to the e-mail and you make it appear as though, yes, you're interested. This offer sounds good to you, and, sure, you'd be willing to invest, but you need a few more details. In one sort of very humorous case, a scam-baiter said "we would love to invest, but we belong to a particular religious order called 'The Holy Order of the Red Breast.' We will only invest if you join our order and send along photos to prove it," in which case the scammer actually did send along pictures of him stripped to the waist with this red symbol painted on his chest. The real goal here is just by wasting scammers' time, you make it less likely that they'll identify an actual victim - and make it less profitable for them as well.

BOB GARFIELD: Apart from catching these guys red-chested, another option is to just shut down the tools of their trade.

JOSH ROSENBLUM: That's correct. These scammers have become more sophisticated. And if you go back to them and say, listen, this sounds good but, you know, I'm really not convinced - is the money really there? - what they may do is send you a link to this fake lottery website or a fake bank website where they can show you, yes, indeed, the 20 million dollars that this wealthy person left without an heir is, in fact, sitting in that bank. And so one of the things that some of these groups have begun to do is to attack these fake bank websites or these fake lottery websites, because these are used more and more as tools to support the con.

BOB GARFIELD: Well, let me ask you this. The next time I get an e-mail that begins, "I humbly beg your attention for a moment as I discuss the problem I have finding an owner for this 20 million dollar inheritance," what should I do?

JOSH ROSENBLUM: Well, you definitely should not reply to it. These people are serious, and there have been murders associated with this scam, both murders by the scammers and revenge killings by people who've been taken advantage of. I think there are several things that you should do. There are several governmental organizations within the United States. The Secret Service and the Internet Crime Complaints Center, which is co-run by the FBI, all take reports of attempts to scam or successful scams. As we've talked about, there are less official organizations that if you forward that e-mail to them, they will either scam-bait that individual or, if that scammer is operating a website as part of the scam, they may try to take down that website, either through legal means or through some of the more aggressive tactics we've talked about.

BOB GARFIELD: Well, Josh, thank you very much.

JOSH ROSENBLUM: Absolutely. I appreciate the time.

BOB GARFIELD: Josh Rosenblum is assistant editor at the now online Legal Affairs magazine.