A federal judge has granted Michael Flynn’s former attorneys permission to withdraw from the legal case surrounding President Trump’s onetime national security adviser.

The development comes after the attorneys, Robert Kelner and Stephen Anthony, notified Judge Emmet Sullivan on Thursday that Flynn was “terminating” them as his counsel and had hired new representation and asked to withdraw from his case. 

{mosads}Sullivan initially denied their motion on technical grounds, prompting them to refile it late Thursday. Sullivan granted the motion in an order on Friday.

The decision by Flynn to fire his Covington & Burling attorneys marks a potentially significant development in his case, though the reasons for their removal remain unclear. Both Kelner and Anthony declined to comment in an email Thursday when asked for more information. 

Flynn has not yet announced his new legal team.

In December 2017, Flynn pleaded guilty to lying to FBI agents about his contacts with the Russian ambassador as part of a deal to cooperate in special counsel Robert Mueller’s investigation.

Flynn cooperated extensively in the probe, according to Mueller, and was expected to be sentenced last December. However, the former Trump adviser elected to delay his sentencing until he is completely finished cooperating with the government after Sullivan harshly criticized him in court and suggested he would receive prison time.

Flynn is expected to testify against his former business partner Bijan Kian, who faces a July trial on charges of acting as an unregistered foreign agent of the Turkish government. Flynn is likely to be sentenced sometime later this year, though a date has not been set.