Federal prosecutors have indicted 20 people in a multimillion-dollar international online fraud scheme.

The case announced Thursday stems from a lengthy investigation out of Kentucky led by U.S. Secret Service agents.

The scheme unfolded on websites like Craigslist and eBay, and the fraudsters would post false ads for expensive items like cars that didn't exist. Prosecutors say they'd persuade American buyers to send money to fictitious profiles, duping them in some cases into thinking the sellers were U.S. military and about to be deployed. They handed over money, but goods never showed up.

The suspects were based mostly in Alexandria, Romania. Prosecutors say they laundered the money using cryptocurrency.

Most of the suspects are foreign nationals. About a dozen have already been extradited to the U.S.

The investigation is continuing.