Federal agents have arrested six people in the U.S. and one in Canada in conjunction with a $140 million international penny stock fraud scheme, one of the largest of all time. They face charges including conspiracy, wire fraud and securities fraud.

From 2008 to this July, these suspects allegedly inflated the values of 12 or more worthless stocks and sold them to victims in 35 different countries, Bloomberg reports. Some of the victims were hit twice—a second scheme collected “advance fees” from purchasers to recoup their losses.

The stocks came from companies with minimal assets that the defendants owned or controlled. To make the stocks seem legitimate, the perpetrators created fake law firms and consulting businesses, and sent out fake press releases about the stocks. They also had call centers in Canada, Thailand and Vietnam, to field phone calls.

“The defendants used our securities markets as a platform from which to run elaborate fraudulent schemes to victimize unsuspecting investors across the globe,” said Brooklyn U.S. Attorney Loretta E. Lynch. “Where others saw citizens of the world, the defendants saw a pool of potential marks.”

The two Canadian Citizens who allegedly organized the penny fraud scheme are still at large.

Read about more fraud cases on InsideCounsel:

U.S. sues PharMerica for fraud

U.S. indicts SAC Capital on fraud charges

Edmunds.com sues company over fake reviews