Richie said he was from Milford, Mass., but that he was out of the country on a big construction job. He was helping build a stadium in Nigeria, he said. As soon as he returned, he promised, he'd come visit Smalley in Ohio. He couldn't wait, and neither could she.

The spirited e-mail romance hummed along for another two months before there was a problem. Richie said his boss paid him in postal money orders, and he was having trouble cashing them. Could Theresa do a small favor for him? Could she cash the money order for him, then wire the money to him in Nigeria? Smalley agreed, and over the next two weeks, she cashed two $900 money orders and sent along the funds. Then, Richie was ready to leave the country, but needed money to deal with a visa problem. She cashed another money order.

Then, Smalley's bank called her. Something was wrong.

"I had to call a special number at the bank. Even up until that point I still believed him. I had no qualms whatsoever cashing (the money orders)," Smalley said. Even after the bank told her the money orders had been altered — they were purchased for $20, but then "washed" and doctored to read $900 — she still held out hope.  But a friend pointed her to an Internet site devoted to Nigerian scams, and suddenly, Smalley's world crashed down around her.

'My whole world had fallen apart'
"The bank told me I was responsible for that money. I had to pay them $2,700, which was everything I had," she said. "I was devastated. I felt like my whole world had fallen apart.

Smalley shared her version of events with MSNBC.com in the hopes that others might not fall for the same trickery.

"Never in my wildest dreams would I have ever known that this is all a part of an elaborate online scam. He spent four months gaining my trust and he did it."

So-called Nigerian scams, where victims are ultimately tricked into sending money to the African country using some irreversible method like a wire transfer, are common. The Secret Service and other U.S. agencies have issued warnings on the scams, also known as "419" or "advance-fee" frauds. But the seductive flavor of this type of the scam — known to some as "sweetheart scams" — and the incredible patience shown by the scammer reveal just how far con artists will go to trick their marks. 

Ryan W. of Washington state, who asked that his last name be withheld, says he sent $15,200 to a similarly seductive scammer. And he wasn't even using an online dating service. Ryan was approached while hanging out in a chat room devoted to Grateful Dead fans. His seducer also claimed to be an American out of the country getting paid via money order, and also ultimately asked him to cash them. Five weeks later, when the bank came calling, all $11,000 in Ryan's bank account — most of it from a student loan earmarked for next semester's tuition — was frozen by his bank.

"Typically people go on the Net to get dates. I was just on there trading music," he said. "The thing that duped me was the whole music issue. She seemed to be into the music I was into."

Flowers bought with stolen credit cards
Nigerian-based con artists seem to have seized on sweetheart scams of late, said Dale Miskall, supervisory special agent in charge of an FBI cybercrime squad in Birmingham, Ala. Scam artists post ads to online dating sites and lurk in chat rooms with names like "40 and single," or "Recently dumped." Often, they reach out to a lonely soul with flowers or candy, purchased with a stolen credit card.

"A little gift of flowers or candy is a good aphrodisiac," said Miskall. "The next thing you know, they are in love. I can't tell you the number of women who have fallen for this."

Eventually, the con artists convince their soulmates to do them a big favor — help transfer funds out of the bank.

Continued