SACRAMENTO, Calif. (AP) — Three men have been indicted on federal charges of defrauding a casino-operating Indian tribe of more than $18 million through a kickback scheme involving the tribal administrator, federal prosecutors said Friday.

Bart Wayne Volen, 53, of San Diego, was arrested Friday at San Francisco International Airport, according to the U.S. Attorney's Office in Sacramento.

Volen, a building contractor, was indicted last week along with former United Auburn Indian Community administrator Greg Scott Baker, 45, of Newcastle, and the tribe's former quality-control expert, Darrell Patrick Hinz, 47, of Cameron Park.

The tribe operates Thunder Valley Casino in Lincoln, a suburb of Sacramento.

Defense attorneys say all three will plead not guilty when they appear in federal court on Monday.

They are charged with conspiracy to commit mail and wire fraud and money laundering in indictments unsealed Friday. The indictment charges that they inflated bills related to a construction project that included new headquarters for the tribe.

Volen, the contractor, is alleged to have paid about $7.5 million in kickbacks to Hinz. Prosecutors say Hinz, the quality-control expert, then used part of his money to buy tribal administrator Baker a Lake Tahoe vacation home, a $54,000 in-ground pool, a $70,000 BMW and a trip to Hawaii, among other things.

In March, the Internal Revenue Service moved to seize 23 properties, including vacation homes in Lake Tahoe and Maui, as part of the investigation.

Hinz's attorney, William Portanova, said the IRS agent's affidavit wrongly infers that the men must have done something illegal because there is so much money involved.

"Inference is not proof beyond a reasonable doubt — especially against a background of Indian gaming, where a single casino can make $2 million in profit, every day, for 365 days a year," Portanova said.

Baker's attorney, Tom Johnson, said his client helped the tribe as its administrator and looks forward to having his name cleared. Volen's attorney, Matt Jacobs, also predicted his client will be vindicated.

If convicted, each faces a maximum sentence of 20 years in prison.