A onetime Faribault state prison inmate is serving federal time after being sentenced for helping file hundreds of thousands of dollars in false tax claims as part of a scheme involving other prisoners and conspirators outside of prison.

Convicted sex offender Tony T. Robinson, 30, of Bayport, was sentenced last week in federal court to seven years in prison, having pleaded guilty in October to conspiracy and false claims charges.

Robinson and Tanka J. Tetzlaff, 40, of Duluth, were behind bars in Faribault in the fall of 2009 when they allegedly recruited other prisoners to file false claims using their names and Social Security numbers. The prisoners used false wage and federal income tax withholding information when filing taxes seeking refunds of more than $500,000, according to the U.S. attorney’s office.

The refunds, paid by check, were deposited directly into bank accounts or deposited onto debit card accounts. Three women not in prison received the checks and cashed them using a power-of-attorney agreement.

The women — Carmen Allen, Vanessa Walberg and Deeanna Crist — have all pleaded guilty to a conspiracy charge. Tetzlaff is scheduled to be sentenced on March 11.

Robinson’s incarceration in state prison ended in mid-December, and he is now serving his federal sentence. His sentence also calls for him to join with Tetzlaff, a convicted drug offender, in paying more than $190,000 in restitution.

These cases are the result of an investigation by the Internal Revenue Service-Criminal Investigation Division, Minnesota Financial Crimes Task Force, and other local law enforcement agencies.