A Burnsville coin dealer pleaded guilty Thursday in St. Paul to federal fraud and counterfeiting charges involving the sale of bogus collectible coins.

Barry Ron Skog, 68, owned the Burnsville Coin Co., which advertised the sale of collectible “numismatic” coins. When buyers responded to his advertisements, he often misrepresented himself as an employee of the company named “Ron Peterson,” though no such person existed. According to plea documents, Skog stole more than $57,000 from his customers and had planned to sell 275 more counterfeit coins for $235,000.

The Star Tribune reported in 2011 that a coin buyer named Robert Webber of Goldsboro, N.C., had complained that Skog and his company were selling counterfeit coins made in China. The coins were encased in sleeves that purported to certify their value by the Professional Coin Grading Service. The owner of the grading company, Collectors Universe Inc., sued Skog for trademark infringement in federal court in California and won a default judgment of $8,230.

Webber said he filed a complaint with the Minnesota Attorney General’s Office and was told that when it started doing research on Skog, investigators learned that he was in China “looking for certain dimes.”

Skog apparently continued selling counterfeit coins, sparking an investigation by the Minnesota Commerce Fraud Bureau and the Burnsville Police Department, which led to the federal criminal prosecution.

The U.S. Attorney’s Office in Minneapolis said authorities believe there may be additional victims of Skog’s scheme who have not yet been identified. It asks that anyone with information about the case call the Commerce Fraud Bureau at 651-539-1617. Callers may remain anonymous.