District Attorney Larry Krasner’s office believes that the judge overseeing Meek Mill’s case has been biased against the celebrity rapper, abused her discretion when she sentenced him to prison in 2017 for probation violations, and should be removed from making decisions in his ongoing appeal.

Those assertions, made in a brief that Krasner’s office filed Wednesday, mark the first time that the city’s top prosecutor — who had already said Mill deserves a new trial — has publicly criticized Common Pleas Court Judge Genece E. Brinkley for her handling of Mill’s case. For months, Mill and his legal team have been accusing Brinkley of ethical improprieties and seeking to have her removed from future proceedings, accusations Brinkley has consistently denied.

The brief, a 37-page document signed by Assistant District Attorney Paul George and three other prosecutors, said that “a reasonable person would question [Brinkley’s] impartiality,” adding: “The public perception of unfairness and bias is exactly what [Brinkley’s] behavior has engendered here.”

In particular, the prosecutors cited Brinkley’s decision to surreptitiously visit a homeless shelter where she had ordered Mill to serve food. They said she had “personally assumed the role of investigator,” then improperly referenced her observations during a subsequent court hearing in which she sentenced Mill to two to four years in prison for probation violations.

Brinkley is barred from responding directly to the allegations due to judicial conduct rules. But her attorney, A. Charles Peruto Jr., said Wednesday that Brinkley “absolutely” denies being biased against Mill. “She has treated him the same way she has treated her other probationers,” Peruto said.

The brief is unlikely to result in any major new development for Mill, at least in the short term. Brinkley last year denied his bid for a new trial, saying she did not believe Mill or the District Attorney’s Office had done enough investigating to prove that the evidence used to convict him was faulty.

The matter is pending in Superior Court. Mill is free on bail as his appeal efforts continue.