Philadelphia's top prosecutor has called for a new trial for Meek Mill.
The 32-year-old rapper spent months in prison after he was sentenced to two-to-four years in jail for minor probation violations related to a 10-year-old gun and drug possession case in November 2017, but District Attorney Larry Krasner has argued Common Pleas Court Judge Genece Brinkley "abused discretion" and was biased against the star.
The DA's office filed a brief questioning the judge's "impartiality" on Wednesday, citing her decision to check in on Meek when he was doing community service at a homeless shelter and later criticising him for not doing more.
The document stated: "Judge Brinkley personally assumed the role of investigator."
The attorney also claimed the judge improperly referred to her own observations at a sentencing hearing and called for Meek to receive a new trial before a different judge as the court had "abused its discretion" when it "imposed" the jail sentence on the 'All Eyes on You' hitmaker.
He had previously had a request for a new trial rejected but is continuing with his appeal efforts.
The judge has denied allegations she was biased against Meek - who was released on court orders last April - during the case.
Jay-Z has previously spoken out to defend his friend.
He said: "What's happening to Meek Mill is just one example of how our criminal justice system entraps and harasses hundreds of thousands of black people every day.
"I saw this up close when I was growing up in Brooklyn during the 1970s and 1980s. Instead of a second chance, probation ends up being a land mine, with a random misstep bringing consequences greater than the crime. A person on probation can end up in jail over a technical violation like missing a curfew."