About 25 unreleased songs by the rapper were discovered online, and investigators traced sales of the music to a former employee, according to federal prosecutors.

A former sound engineer for award-winning rapper Eminem—also known as Marshall Mathers—was charged on Wednesday with stealing the rapper’s unreleased music and selling it for Bitcoin, according to federal prosecutors.

"The significant damage caused by a trusted employee to Eminem's artistic legacy and creative integrity cannot be overstated," a spokesman said.