It was an elaborate scam that turned into a Ponzi scheme.  But none of the investors had a clue.

"It did actually begin as a legitimate business," said U.S. Postal Inspector Raymond Campbell.

But the owner of Global Gold and Metals Trading made a wrong turn and swindled more than $6 million from customers trying to buy precious metals online.

"He was selling products at below market value. He was selling it at a discounted rate, which ultimately attracted the consumer to purchase from him, but he couldn't sustain that," Campbell added.

Postal inspectors say Earl Mohammed was making good on the first several orders to gain his customers trust.  But once they put in a more sizable order, he would claim the package was sent. Authorities say that was a lie.

"What he did is he provided the consumer with a postal service tracking number, he would actually pay postage for the tracking number and he would tell them it was en route," explained Campbell. "Ultimately it would never arrive at the consumer's home or residence, they would call Mr. Mohammad, ask where the items were and he would say the postal service lost them."

Postal inspectors say the excuses were Mohammed's way of "buying time" for new money to come in.  Another excuse: He'd claim he filed an insurance claim but it would take time to get the consumer a refund.

"Consumer fraud actually became a Ponzi scam. He was using new customer money to repay old customers that were still awaiting their precious metals," Campbell said.

Inspectors say the average investor lost between $50,000 and $75,000.

"A lot of these individuals ended up invested their life savings, retirement funds; several homes that have now been foreclosed on," said Campbell. "We are still working to locate funds. We suspect there may be concealed funds."

The fact is all investments carry risk.  Inspectors say do your due diligence.

"Research the company you are going to do business with. Secondly, if you believe you've been scammed, make sure you report it to law enforcement," advised Campbell.

Mohammad pleaded guilty mail fraud. He was sentenced to nine years in federal prison and will have to repay $6.5 million in restitution.