The five had been convicted of conspiracy and mail fraud.

The primary salesman in North Carolina, Arthur J. Anderson Jr., 49, of Raleigh, was sentenced to five years in prison, U.S. Attorney George Holding said.

Michael Lomas of Pasadena, Texas, was sentenced to 20 years in prison; Scott B. Hollenbeck, 53, of Orlando, Fla., to 14 years; Laurinda Holohan, 63, of Concord, Ohio, to eight years; and Susan Knight, 48, of Eastlake, Ohio, to 2 1/2 years.

The group, operating under the name Mobile Billboards of America, sold truck advertising billboards to mostly elderly investors for $20,000 each. The billboards were supposed to yield a return of 13.49 percent for seven years, and investors would be paid in monthly checks.

But the scheme did not generate ad revenues. It relied on new investors to pay the leasing fees for previous ones.

Hollenbeck and Holohan were convicted by a federal jury after a four-week trial and a four-year investigation. Most of the remaining business associates pleaded guilty.

Prosecutors say another business associate, Michael L. Young, 61, is a fugitive, hiding in the United Arab Emirates.