The father and son were among four men arrested in October on charges of conspiring to commit bribery and wire fraud. Authorities accused the men of inflating invoices during a four-year period and then collecting tens of millions of dollars for themselves and co-conspirators.

Prosecutors said Kerry Khan signed a statement of offense that said that in or around 2006, he and colleagues agreed to work together to obtain government contracts for corrupt contractors who would reward them with bribes. Authorities said their investigation continues, but they have found eight people to have have been part of this scheme.

Among others, Kerry Khan and Michael A. Alexander, also an Army Corps of Engineers program manager, worked with Harold F. Babb, a contractor, on their plot to use a company called EyakTek as a vehicle for channeling contracts awarded by the Army Corps of Engineers. EyakTek then hired subcontractors that submitted fraudulently inflated estimates or prices for equipment and services, authorities said.

The subcontractors kicked back a significant portion of the excess funds to Kerry Khan and Alexander as bribes for keeping the money flowing their way, officials said.

Prosecutors said Khan and his son admitted to establishing multiple corporations and shell companies to hide the money and purchase real estate, including several houses and condos. Lee Khan managed the portfolio of properties and automobiles purchased using the bribe money, by leasing the homes to tenants or selling vehicles, officials said.