A man who once worked as a sound engineer for rapper Eminem was charged 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, Michigan, worked for four years at Eminem’s studio in Ferndale, Michigan, 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 FBI affidavit.

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.

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.

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 FBI.

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

The hard drives are protected with passwords and stored in a safe when not in use, according to the affidavit. It noted that only four employees had access to the hard drives from 2007 to 2021, and that only one of those employees, Joseph Strange, no longer works there.

When Eminem, whose real name is Marshall Mathers III, learned that his music had been leaked, one of his employees sent out a social media post warning his fans not to spread the leaked music. An unidentified tipster responded and told the FBI about having been in online chats with an Eminem fan who used the screen name Doja Rat.

Doja Rat, a 31-year-old man in Ontario, Canada, told FBI investigators that he had bought 25 unreleased songs from Strange for about $50,000 in bitcoin, beginning in the summer of 2024.

The FBI, which obtained a search warrant for Strange’s home, found many of Eminem’s original handwritten lyric sheets in a safe there during a raid in late January, a special agent for the FBI said. They also found a VHS tape of an unreleased music video. An image of that tape had been sent to Doja Rat and a buyer from Connecticut, the FBI said.