Washington (CNN) The federal judge overseeing the criminal case against former Trump campaign chairman Paul Manafort expressed exasperation Wednesday about his separate lawsuit challenging the appointment of special counsel Robert Mueller.

Federal Judge Amy Berman Jackson grilled Manafort attorney Kevin Downing for 50 minutes in open court over whether Manafort had the ability to bring the civil lawsuit against the Justice Department.

Previously, Manafort's attorneys complained that Mueller exceeded his authority by opening cases against Manafort, because they involved business conducted years before he joined the Trump campaign in 2016.

Yet that was no longer an issue Wednesday, and instead will stay part of the legal arguments in his criminal case. Downing said in court they've changed the civil complaint they have about Mueller's investigation to say that they now think only Deputy Attorney General Rod Rosenstein overstepped his authority when he appointed Mueller.

Manafort's lawyers also asked the federal court to stop the special counsel's office from bringing additional indictments against Trump's former campaign chairman.

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