Authorities are investigating a "large-scale tax refund scheme" run by Minnesota prisoners.
The Star Tribune reports the investigation focuses on a 28-year-old inmate who's currently serving a 91-month sentence for first-degree sexual conduct and is due for release on May 15.
According to a search warrant affidavit filed by an investigator with the Internal Revenue Service, the prisoner allegedly charged other inmates from various Minnesota prisons to prepare bogus tax returns.
A rented UPS mail drop was used to receive refund checks from the U.S. Department of Treasury, which were later deposited into bank accounts by an outside accomplice.
The court document details tax returns filed by several current or former inmates convicted of premeditated murder, robbery, assault, weapons charges, theft, stalking and burglary.
The amount of money obtained is unclear, but the case involves hundreds of fraudulent returns over a six-year span.
Charges have not yet been filed.