LOS ANGELES—A co-owner of a Hollywood video game store that caters to celebrity clients on Wednesday pleaded guilty to participating in a conspiracy to violate federal copyright laws by selling Xbox video game consoles modified to play pirated games.

Jason Jones, a co-owner of ACME Game Store, entered a guilty plea in federal court in Los Angeles. His business partner, Jonathan Bryant, has signed a plea agreement and is scheduled to plead guilty to a conspiracy count on Monday, prosecutors said.

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