(MONEY Magazine) – Imagine turning on your computer and finding an e-mail like this.

CONFIDENTIAL: Dear Sir, Good day and compliments. This letter will definitely come to you as a huge surprise, but I implore you to take the time to go through it carefully as the decision you make will go off a long way to determine the future and continued existence of the entire members of my family.

Please allow me to introduce myself. My name is Dr. (Mrs.) Mariam Abacha, the wife of the late head of state and commander in chief of the armed forces of the federal republic of Nigeria who died on the 8th of June 1998.

My ordeal started immediately after my husband's death on the morning of 8th June 1998, and the subsequent take over of government by the last administration. The present democratic government is determined to portray all the good work of my late husband in a bad light and have gone as far as confiscating all my late husband's assets, properties, freezing our accounts both within and outside Nigeria...

My late husband had/has Eighty Million USD ($80,000,000.00) specially preserved and well packed in trunk boxes of which only my husband and I knew about. It is packed in such a way to forestall just anybody having access to it. It is this sum that I seek your assistance to get out of Nigeria as soon as possible before the present civilian government finds out about it and confiscate it just like they have done to all our assets.

I implore you to please give consideration to my predicament and help a widow in need.

May Allah show you mercy as you do so.

Your faithfully, Dr (Mrs.) Mariam Abacha (M.O.N)

What Dr. (Mrs.) Abacha is saying here is that she's so desperate for help moving this $80 million that she has been reduced to sending plaintive e-mail messages to regular people she doesn't know in America. Most sane people, upon seeing that sort of thing in their In boxes, realize the letter isn't really from Mrs. Abacha, assume that it's a scam or a joke and simply hit delete.

Others, however, take the bait. They respond, tentatively at first, but also with a furtive glimmer of hope or greed or anxiety that can be used to turn even a levelheaded citizen into a gold-plated sucker. E-mail exchanges and phone calls follow. Over time, bit by bit, the proposition starts to seem real: Help move the money and get a cut of that $80 mil.

Eventually the mark finds himself talking to a very intelligent and persuasive person with an African accent who has been designated to act for Mrs. Abacha. The African will describe several trunks packed with $100 bills, all of which have been dyed black or stamped with red to prevent them from being stolen. He'll produce official-looking documents concerning the money. He'll even produce a few genuine bills and clean them with a mystery solvent. It will be explained that transporting, storing, insuring and cleaning the rest will require money--maybe $50,000--in exchange for which Mrs. Abacha's agent will offer a hefty slice of the $80 million. Convinced by the cleaned bills that he's seen with his own eyes, the mark will raise the money (maybe enlisting friends and family to help), deliver it and wait for the payoff.

But there will be delays. More money may be required to pay an export duty or to bribe Nigerian customs officials. Then even that won't be enough. More will be needed. And then more again. Eventually Mrs. Abacha's representative will disappear. Eventually the mark will realize he's been had.

SECOND ONLY TO "HERBAL VIAGRA"

This kind of advance-fee scam--or 419 scam, for the section of the Nigerian penal code that covers it--has been a thriving enterprise for at least 20 years. It is, by some estimates, the second-largest industry in Nigeria, after oil.

Only a tiny fraction of the people who receive an advance-fee pitch fall for it, of course. But if you increase the number of appeals--and, thanks to the Internet, they are increasing at an alarming rate--the number of suckers grows proportionately.

In addition, there's reason to believe that fraction has been growing as well: Scams of all kinds flourish when times are good and the stock market is hot, conditions that until recently prevailed here in the U.S. According to the U.S. Secret Service, which polices such scams in this country and recently opened a branch office in Lagos, Nigeria, to fight them, West African advance-fee scams have cost Americans $100 million over the past three years.

How did Nigeria become such a prolific source of those swindles? Having been on the receiving end of generations of colonial rule, the populace of Nigeria (and neighbors like Ghana and the Ivory Coast) is generally well educated, English-speaking and very poor. After gaining its independence in 1960, Nigeria suffered decades of freewheeling official corruption, exacerbated by religious and ethnic strife and greased by money from the country's oil and mineral resources. U.S. law-enforcement authorities say Nigerian president Olusegun Obasanjo appears serious about cleaning things up, but the task is huge and the progress, by all accounts, glacial. In its most recent Corruption Perceptions index, the nonprofit monitoring group Transparency International ranked Nigeria second only to Bangladesh in crookedness.

In short, Nigeria--Africa's fastest-growing country--has become a place where even honest people learn to game the system just to survive. And in that environment, it's only logical that the real crooks would be very good at what they do. It's also logical that this talent would busy itself fleecing the English-speaking world's largest pool of wealth. Bruce Townsend, chief of the Secret Service's financial crimes division, says West African gangs are well organized and have diversified into things like bank fraud, identity theft and drug dealing.

Their sophistication naturally extends to technology, so the once laborious business of trolling for suckers is now done easily, quickly and anonymously via bulk e-mail and fax. "It's very easy," a spokesman for Nigeria's antifraud agencies told the newspaper Newswatch. Would-be scammers merely walk into one of the country's many Internet cafes and set up an online account. "All it costs," he added, "is a few hundred naira." The equivalent, that is, of about three U.S. dollars. The Washington, D.C.-based National Consumer League says that West African advance-fee fraud is now the third biggest consumer come-on on the Internet. According to antispam software maker Brightmail, the only kind of junk e-mail more common are pitches for "herbal Viagra."

That some Americans will fall for almost any well-packaged financial scheme, no matter how insane, has long been understood by both freelance con artists and their Wall Street cousins. (The box on page 111 offers a brief look at some of the 20th century's most notorious examples.) But a handful of Americans have lost more than money to Nigerian scams, usually when they've been convinced to go to Africa or Europe, where they're more vulnerable. Last August, Kenyan police rescued three kidnapped Americans who'd been lured to Nairobi by a Nigerian gang. A year earlier, Jerry Stratton, a Florida plumbing contractor who'd been bilked of about $67,000, went to London deluded into thinking he could recover his money from the West African "businessmen" with whom he'd been dealing. Ultimately, Stratton killed himself in his hotel room, leaving a note. "If anything happens to me," it read, "look for three people. They are Nigerians. They are responsible."

"GOING SHOPPING" WITH BUZZ SILER

On paper, advance-fee come-ons seem so preposterous that it's hard to see how anyone could fall for them. Swindling, though, is a kind of theater, and a gifted performer can make even the most tired script come to life. The best Nigerian con artists are experienced, sophisticated and quick to adapt to changing circumstances and exploit newly glimpsed weaknesses. (Recent waves of e-mail have incorporated post-9-11 angles, in some instances, invoking the fortune of a rich Nigerian, killed in the attacks, who left no heirs.)

A rare glimpse into such artistry comes to us via Lawrence "Buzz" Siler. A Portland, Ore. inventor who runs a company that makes money pouches and other security gadgets for banks, Siler got a fax from the ubiquitous Mrs. Abacha, describing $25.6 million she wanted invested on her behalf in the U.S., in the autumn of 2000. "Obviously somebody offering you $25 million is pretty ridiculous, so I wrote back just to see where it was all going," Siler says. He also called the FBI, which put him in touch with the Secret Service, which in turn enlisted him as an undercover agent.

Soon Siler was getting a steady stream of pitches from several would-be scammers, among them one Victor Okiti, a Nigerian who, it turned out, had twice entered this country under a false identity. Siler says the tenacity and professionalism of the various con men who contacted him was impressive. Like all adept salesmen, they tailored their spiel to the mood of their target. When Siler seemed to respond to the soft sell, they'd sweet-talk him. Once, when he balked at putting down a $25,000 advance fee, Okiti berated him about all the people who'd taken risks on his behalf. Siler spoke to Okiti and others innumerable times over a period of months. Bit by bit, he says, the deals that at first seemed so phony almost started to seem real. "There was a very thin line that I could have stepped over to start believing these guys," he says.

While continuing to string along Okiti, Siler met with two other teams of scammers in Atlanta hotel rooms, each time bringing along money provided by the Secret Service and a female agent posing as his girlfriend. Once each transaction was done, Siler was to say a prearranged code phrase and a group of armed agents would burst in from the adjoining room and make arrests. (The busts didn't go off without a hitch: During one of the two Atlanta stings, Siler had to say--then shout--the code words "go shopping" three times before the agents heard him.)

Then last summer Siler met Victor Okiti in a Houston hotel room. Okiti showed him a trunk of $100 bills, each stamped with "UN"--meaning, he was told, unnegotiable. Naturally, they would need to be cleaned. Secret Service agents videotaped the meeting via hidden camera and arrested Okiti. Last August he pleaded guilty to wire fraud and counterfeiting and is now serving an 18-month federal sentence.

A PHILADELPHIA STORY

Many con men have mastered the technical aspects of their craft: careful preparation, meticulous documentation, back-up stories and the like. Perhaps what distinguishes the true artists among them is an ability to turn their dupes into quasi-accomplices. Astonishingly often, the swindle-ee actually expedites his own fleecing through a kind of temporary insanity, a willingness--or desperation--to suspend disbelief and prolong the possibility of getting rich quick. The most interesting (not to mention, weirdest) example of this phenomenon may be the advance-fee fraud case of Edward Mezvinsky, a 64-year-old former Democratic congressman from Iowa.

A onetime liberal folk hero who, as a member of the House Judiciary Committee, voted to impeach President Nixon in 1974, Mezvinsky later served as President Carter's representative to the U.N. Commission on Human Rights, before setting himself up as a Philadelphia-based lawyer and self-described international businessman. He is scheduled to go on trial in Philadelphia this fall to face a 66-count federal indictment accusing him of stealing some $10.4 million. The list of alleged victims includes not only numerous banks and business associates, but also several longtime friends and his mother-in-law. His wife Marjorie Margolies-Mezvinsky, also a former member of Congress, was thought to have a bright future in national Democratic politics until her husband's fall.

Some of the frauds Mezvinsky is accused of were fairly simple affairs with no connection--directly, anyway--to West African cons. But he was also involved--sometimes as scammer and sometimes as sucker--in several deals that come straight out of the Nigerian playbook. Starting in the early 1990s, Mezvinsky found himself being tapped repeatedly by a parade of West Africans. According to Robert Zauzmer, the assistant U.S. attorney prosecuting the case, a "sort of mailing list of potential victims" appears to circulate along the Nigerian grapevine. (This explains why Buzz Siler got so many pitches--and why he was able to help bust three separate groups of scammers.) Mezvinsky must have been a con artist's dream: an apparently upstanding American pol who's financially ambitious and has access to wealthy friends and banks only too happy to lend him money.

Most significantly, however, it appears Mezvinsky believed, or wanted to believe, their increasingly crazy pitches. (He declined to be interviewed for this article.) Of the approximately $13.3 million that flowed through Mezvinsky's bank accounts between 1995 and 2000--most of it, says Zauzmer, the product of fraud or embezzlement--about $2.6 million went to con men, a portion of which turned up in bank accounts in New York City and Boston that federal investigators believe were controlled by West African swindlers.

Starting in the late 1980s, according to Zauzmer, Mezvinsky got involved in a series of shady dealings. He began scamming a long list of victims, many of them friends, promising big returns from West African oil or investment schemes. Starting in late 1996, Mezvinsky solicited $365,000 from a Maryland urologist. A year later he got $1 million from a certified financial planner in Florida. Between January 1998 and January 1999, he received $1.2 million from an Italian businessman. In 1999 he got yet another $1 million from a retired Pennsylvania business executive and $500,000 from a Virginia investor. Each got a different story, but the general pitch was that if they would give Mezvinsky their money--which he promised to hold in trust at a U.S. bank, risk-free--he would guarantee a hefty and quick profit.

But even as Mezvinsky was scamming people, he was letting himself get scammed by West Africans--apparently hoping that the big score would help him pay off the large debts he was accumulating.

The whole thing crashed to earth when David Sonders, the Virginia investor, sued. Soon after, in January 2000, Mezvinsky and his wife declared bankruptcy. The filing shows debts in excess of $7 million, much of it unsecured personal loans from friends and business associates, including $25,000 lent in 1999 by Bernard Nussbaum, a prominent New York City attorney and President Clinton's first White House counsel. (Nussbaum declined to discuss the matter.) Mezvinsky's wife pulled out of the race for the Democratic nomination to one of Pennsylvania's U.S. Senate seats.

Amazingly, even all that public humiliation wasn't enough to scare him away from African hustlers. Just six months later--by which time FBI agents were looking into his affairs--Mezvinsky convinced Robert Farrell, a Maryland friend and business associate, to fly to Chicago to scope out a deal for him. Farrell says he was met at Chicago's Midway Airport by a man with an African accent and a gun who drove him to a self-storage facility near the University of Chicago. There he was shown a wooden chest supposedly containing--what else?--$81 million in $100 bills, dyed black. At a nearby motel, a second African, a "Mr. Timothy," produced a vial of liquid, poured it into a bucket of water and soaked some of the bills. They were rinsed and dried and given to Farrell, who was driven back to the airport with bills in hand. Farrell says he doesn't know if the deal proceeded further.

Meanwhile, Mezvinsky--who since December has been confined to his home by a federal judge and ordered to wear an electronic monitoring bracelet--is mounting an unorthodox defense. His lawyers argue that any responsibility he may have is diminished by a combination of manic depression and Lariam, an antimalarial drug that is, in fact, known to cause unpleasant temporary psychological effects in some people. (Mezvinsky also sued Hoffman-LaRoche, the maker of the drug, and the doctor who had prescribed it, a longtime friend.)

A federal judge will rule this summer on whether he'll allow the mental-health defense. If not, and Mezvinsky is found guilty, he could spend seven years in federal prison. One way or another, he's likely headed for jail--but the Africans who defrauded him are not. No doubt they're as far away from Philadelphia as they can get, whoever they are. Which in one respect makes the whole Mezvinsky fiasco, for all of its convolutions, a typical Nigerian advance-fee swindle. The mark has been fleeced, his money has vanished, and no one knows who or where the scammers are.