How one African man's gold scheme cost his American victims millions of dollars

— -- There’s nothing quite like seeing $100 million worth of gold with your own eyes -- heaven may be the closest thing.

That’s the blunt concession of an Atlanta businessman who fell for one of the most sophisticated -- and most convincing -- scams U.S. law enforcement has ever seen, allegedly made possible with the help of corrupt government officials in Africa.

“I challenge anybody that would have been there, I don't care who you are, what walks of life you came from, I challenge you to go and see and do the things that we've done, and not” fall for it, the 62-year-old businessman told ABC News under the condition that he not be identified by name.

Watch the full story on "Nightline" TONIGHT at 12:35 a.m. ET.

The man behind the scam, Liberian native Cassell Kuoh, is now living in a U.S. federal prison near Charlotte, North Carolina, after pleading guilty to fraud charges and opening up to authorities about his wide-ranging scheme.

“When I heard the dollar amounts that were involved I was shocked. I was literally shocked,” said Chris Healy, the assistant special agent in charge for Homeland Security Investigations in Charlotte, which investigated the case. “Not $1, $2, $3 or $4 [million]. We're talking anywhere $25 to $30 million.”

For the Atlanta businessman, this international caper started three years ago, when he received a call from an associate telling him about a miner in Liberia named Cassell Kuoh, who by all accounts was a Liberian success story.

He founded one of Liberia’s preeminent soccer teams; he was a philanthropist in his impoverished community, and -- the businessman was told -- Kuoh was a mine operator with a warehouse full of gold and diamonds, worth hundreds of millions of dollars.

He was described as “a Liberian up-and-coming businessman that could be trusted to do transactions … and they actually called me to see if I wanted to invest,” the Atlanta man recalled to ABC News.

He wanted to be a part of it all, but first he had to know if it was the real deal -- was Kuoh truly as he was being billed?

So the Atlanta man emailed with Kuoh, he researched Kuoh, he met Kuoh in New York City and tested the miner’s product, and then he flew to Liberia.

While in Liberia, the Atlanta man visited Kuoh’s mining site, he visited with officials of the Liberian government, he went to Kuoh’s home and met his family, and he went to Kuoh’s office -- an episode that the Atlanta man captured on his cellphone.

“For all the non-believers that the product is real, you can actually see now, here’s 400 kilograms [nearly 900 pounds] of gold,” the Atlanta man can be heard saying as he shows Kuoh opening up seven white sacks filled with gold. Piled next to the sacks of gold were nearly two dozen gold bars.

“These are just some of the products,” Kuoh told ABC News. “There are more of them that we have.”

Kuoh had produced the same show for so many others -- using even more theatrics. In some cases, bullet-proof vans guarded by armed men would drop off the gold.

“What they see is unbelievable. The set-up is very big,” Kuoh said.

Those who traveled thousands of miles to see the gold also got to test the gold however they liked.

All the clients had to do -- they were told -- is pay for any costs, certifications and taxes needed to export the gold out of Africa. Then they can sell the gold and split the profits.

According to Kuoh, people from all over the world jumped in, including investors from the United States, United Arab Emirates, South Africa, India, Iran, Saudi Arabia and Qatar.

But Kuoh acknowledged that he had a secret.

“The gold is not my gold. The gold is the government’s gold,” he said.

His family’s mine produced little gold or diamonds. So, Kuoh told ABC News, he paid Liberian government officials to let him use ministry gold as a prop for the day.

“I don’t have 500 kilos [about 1,100 pounds]!” he declared. “But the government has tons of gold. So if this person needs to see 200 kilos [nearly 450 pounds], we get the 200 kilos.”

Sometimes, Kuoh would take the show on the road to other African countries and pay government officials or gold refinery operators there to help make it happen.

“Everywhere in Africa they have the same set-up,” he said. “You just need to go to one of the groups and deal with them, and you talk percentage.”

As Homeland Security Investigations official Patrick Healy put it, Kuoh “had hooks within governments and these government agencies, and some of the money that Kuoh derived from some of these victims was to pay off these government officials.”

Cassell also set up a fake website, so clients could track their shipments. The website was constantly being updated with new stories, new unforeseen hitches and new reasons that clients needed to pay just a little more to keep the shipment coming.

“If you know a thing about customs, a lot of things get stuck in customs, cars, all kinds of commodities, always, it's not something that is not normal … I had no reason, in my own mind, not to believe it,” the Atlanta businessman told ABC News.

But “the truth of the matter,” Kuoh said, was “there is no package.”

“We just keep giving you another story, keep giving you documents. We’ve been shipping the gold for 10 years, [but] you can’t get it,” he said.

It was a vicious cycle.

“You're so deep in, you've got to get out somehow okay. … We needed to raise funds,” the Atlanta businessman man said. “That's when I borrowed money and brought in some other close friends and relatives.”

Meanwhile, Cassell was becoming a rich man, buying expensive cars, traveling the world, and living a life of luxury.

He even used cash to buy a house in Charlotte for his wife and kids – perched on Happiness Road, right off Perseverance Drive (really).

“He was enjoying life in America,” noted Jill Rose, who oversaw the prosecution of Kuoh as U.S. attorney for the Western District of North Carolina. She is now serving the Justice Department overseas.

For a long time, Cassell thought he would never get caught and that he would be protected by the top-level Liberian government officials involved in his criminal conspiracy.

“No one was going to touch me,” Kuoh said. “And trust me, no one could have touched me when I was going to be in Africa.”

He was beloved by the impoverished Liberians around him for the real things he did.

“He wanted to take care some of his people,” the Atlanta businessman said. “I think he donated regularly lots of money to his church. And I know for a fact he fed a lot of people in the city and, you know, we would stop and would buy fish for the children.”

According to Kuoh, he helped send several children in his community to school and he used some of ill-gotten gains to place 24 hand pumps in his village for safe drinking water.

The Atlanta business said that’s one of the things that first attracted him to Kuoh.

“My mission was not to get into this to be rich, I was going to be rich just in theory in doing it for a purpose,” said the businessman, who ended up losing all of his money and all of the money he brought in from others.

In total, he squandered as much as 8 million dollars, he said.

The whole scheme came to an end in November 2016, the morning after Kuoh flew from Liberia to see his family in North Carolina. He had just gotten his kids ready for school.

“There was a knock on the door,” Kuoh recalled.

An agent from Homeland Security Investigations wanted to ask him some questions.

Kuoh said he was initially “unfriendly” in his answers, but then the agent declared, “We have a warrant to arrest you.”

The Atlanta businessman recalled: “When I received a call that he had been arrested, I had no earthly idea why anybody in the world would want to arrest Cassell. … I spoke to him almost every day for three and a half years, and I guess there is two sides of him.”

In fact, Kuoh said one of his victims still doesn’t believe it was all fake. And in his interview with ABC News, Cassell offered this message to the victim: “Please, please stop giving money to people. I got information you recently give money to people in Kenya again, just two or three weeks ago. … Stop. It’s a scam. Please! It is a scam.”

Cassell has since pleaded guilty to a wire fraud conspiracy. He is cooperating with authorities, and hoped for a reduced sentence by telling his story.

He is now serving more than seven years in prison, and he was ordered to pay nearly 17 million dollars in restitution.

He said his arrest was the best thing that ever happened to him.

“It may sound funny to you, but I appreciate god a whole lot for me being caught,” Kuoh said. “Because I was going on the wrong path. Now that I’m caught, at least at this age, I have time to rewrite my name.”

But he warned that there is still a global army of scammers out there, saying, “There are so many. I can’t count them. They are in the thousands. There are so many. … And people get victimized every day. Every day.”

As for his own victims, he said he still thinks about all of them – especially the Atlanta businessman.

“I deeply regret being part of a syndicate that led me to this, and I owe them a lot,” he told ABC News as his eyes began to shed tears. “I really do owe them a lot. But this is the point of transformation. At least they can know that no one else will be victimized by me.”

The Atlanta businessman may be a little skeptical.

“This man could cry on the drop of a dime, for two or three days if he’d like,” the Atlanta man said of Kuoh. “This is how good Mr. Cassell is.”

Rose, the former U.S. attorney who helped prosecute Kuoh, was similarly dubious.

“While I appreciate the apology, it's a little bit too late,” she said.

The Liberian embassy in the United States didn’t respond to ABC News' request for comment about Kuoh’s accusations. But after Kuoh’s arrest, a top Liberian official sent a letter to U.S. authorities, applauding the arrest and expressing “grave concern” that “unscrupulous individuals” may try to exploit the country’s gold and diamond industry.

“[T]his is a serious problem that cannot be condoned and needs to be solved,” the letter said.

The letter denied any knowledge of government officials assisting Kuoh.

As for those who did help Kuoh, Rose had a message for them: “We're coming for you.”