Duncan, 45, and Kenny Avery, 48, also of Smithville, were indicted July 2, 2010, in a fraudulent invoice scheme related to BNSF railroad vendors.
The scheme ran from Jan. 1, 2003, to Nov. 13, 2005, when Duncan and another man wrote fraudulent invoices for more than $350,000.
Duncan and Avery pleaded guilty, and Avery was sentenced to six months in prison and to pay $120,000 restitution.
Others associated with this scheme were prosecuted in north Texas on up to nine counts each. One was sentenced to 63 months and to pay $1.28 million in restitution and another to 51 months and $922,044 restitution.