U.S. District Judge Kenneth A. Marra of the Southern District of Florida ruled Thursday that prosecutors broke federal law in their handling of a case against Florida billionaire Jeffrey Epstein, who ran a global child sex ring between 1999 and 2007.

According to Marra’s ruling, former Miami U.S. Attorney Alexander Acosta was wrong to set up a clandestine nonprosecution agreement with Epstein in 2008 that shielded him and his accomplices from federal prosecution.