Federal prosecutors on Tuesday said a West Virginia letter carrier committed attempted election fraud by altering party affiliations from Democrat to Republican on requests for absentee ballots.

The clerk of Pendleton County in April received seemingly altered requests from eight voters, five of which had been changed from Democrat to Republican. The request was altered but the party was unchanged on the other three, according to the U.S. Attorney’s Office for the Northern District of West Virginia. The alterations appeared to have been made with a black pen, according to the U.S. attorney’s office.

The man, Thomas Cooper of Pendleton County, admitted to altering requests and said it was intended as a joke. Cooper was responsible for mail delivery for the three towns from which the doctored requests were mailed — Onego, Franklin and Riverton.

The U.S. attorney’s office has charged Thomas with one count of violating a statute that imposes criminal penalties for anyone who “knowingly and willfully deprives, defrauds, or attempts to deprive or defraud the residents of a State of a fair and impartially conducted election process, by ... the procurement, casting, or tabulation of ballots that are known by the person to be materially false, fictitious, or fraudulent under the laws of the State in which the election is held.”