A man who once worked as a sound engineer for the rapper Eminem was charged on Wednesday with leaking and selling his unreleased music online for about $50,000 in Bitcoin, according to federal prosecutors.

The man, Joseph Strange, 46, of Holly, Mich., worked for four years at Eminem’s studio in Ferndale, Mich., near Detroit, but lost his job in 2021, court records show. Under an agreement that was part of his severance package, he was specifically prohibited from electronically circulating Eminem’s work, according to an F.B.I. affidavit.

Mr. Strange sold about 25 songs that Eminem wrote from 1999 to 2018 but which were still in development, prosecutors said. They were played, shared or sold online without Eminem’s consent or that of the Interscope Capital Labels Group, which owns Eminem’s music, according to the court documents.

Mr. Strange has been charged with copyright infringement and interstate transportation of stolen goods, the U.S. Attorney’s Office for the Eastern District of Michigan said.

The authorities were alerted to the illegal leaks and sales in January, after current employees at Eminem’s studio learned that his music was being played online, on sites including Reddit and YouTube, court records show. They recognized the music as unreleased versions and reported it to the F.B.I.

“They were able to identify the music as having been stored on hard drives in the studio in Ferndale,” the F.B.I. affidavit says. “These hard drives are not connected to the internet for security reasons.”