The Federal Trade Commission said Thursday it has temporarily shut down a Belize real estate investment scheme that it says targeted U.S. senior citizens, calling it the largest such scam it has ever encountered.

James Kohm, associate director of the FTC's division of enforcement, said Sanctuary Belize raked in $100 million while marketing false promises about dream retirement homes in a luxurious resort. He said the scheme primarily targeted U.S. residents and small-business owners near retirement age.

The action underscored the flaccidity of the FTC's civil enforcement muscles, when Kohm revealed that Andris Pukke, a convicted California felon who it says established the scheme, allegedly ran the operation even while he was serving 18 months in prison for obstruction of justice related to a previous investment scheme, according to the federal complaint.

Pukke could not immediately be reached for comment. Pukke is represented by Pamela Thakur, founder of the Thakur Law Firm in Anaheim. She also was not immediately available for comment.

Kohm also said the Belize property, which Pukke owned, was ordered seized in the previous U.S. action against Pukke, but that he was able to obstruct the receiver from taking control.

The legal action listed as defendants seven named individuals, including Pukke; 15 real estate or marketing companies; one Belize bank; and a property owners association. Four of the defendants reside in the U.S.—Pukke, Peter Baker, Luke Chadwick and Frank Costanzo—and all have been ordered not to leave the U.S. without court approval.

The FTC was granted the temporary restraining order, which also froze defendants' assets, by the U.S. district court in Maryland. The agency has also filed a 47-page complaint against the same defendants seeking a permanent injunction and seizure of all assets in hopes of reimbursing duped investors.

Kohm said his agency used people posing as owners of a small exercise and fitness business to engage with the sellers. The FTC even created a fake website for the business. He said the effort was “more robust” than the usual sting operation.

According to the FTC, the defendants allegedly operated a set of interrelated businesses and ran commercials on Fox News and Bloomberg News advertising parcels of land that were part of the luxury development in Belize. They also advertised the property through infomercials on national TV. Consumers who expressed interest would receive a call from California-based telemarketers who then made a series of false claims including about what the complex offered, when it would be finished and how much lots would appreciate.

Although the FTC's investigation is still ongoing, Kohm said it is believed that at least 1,000 investors lost money.

Specifically, the FTC charged the defendants with violating the FTC Act and the Telemarketing Sales Rule. In addition, it charged Belize's Atlantic International Bank with assisting and facilitating the Belize scheme. A phone number for the bank listed on its website was disconnected, and it did not immediately respond to an email.

The FTC has also filed a contempt motion against defendants Pukke, Baker and John Usher related to Sanctuary Belize; a second contempt motion against Pukke and relief defendant John Vipulis seeking money Pukke owes the commission; and a third contempt motion against Pukke, Baker and Usher seeking to unwind a prior real estate transfer to enable the FTC to secure the unsold portions of the Belize land parcel.

The court documents remain under seal for the time being, but the commission has posted most of them on its website.

The case is being heard by U.S. District Judge Peter Messitte of the District of Maryland. The court has set a Nov. 19 hearing to determine whether to issue an injunction and continue the freeze on defendants' assets.

The FTC is represented by its general counsel, Alden Abbott, and staff attorneys Jonathan Cohen, Benjamin Theisman, Amanda Kostner and Khouryanna DiPrima.

This article has been updated from an earlier version with additional detail.