Prosecutors are getting frustrated with the lack of information they’re getting from former Trump campaign chairman Paul Manafort since he agreed to cooperate as part of a plea deal in October, ABC News reported Friday.

A source told ABC News that special counsel Robert Mueller’s team is “not getting what they want,” despite a plea deal that outlined a broad scope of cooperation.

According to the report, some of the questions prosecutors have asked Manafort focus on Roger Stone, the Trump ally who Manafort once worked with at a lobbying firm back in the 1980s.

The little information that Manafort has offered to prosecutors — who have asked questions about Stone from his lobbying days in the 1980s through 2016, when Stone was informally affiliated with the Trump campaign — has not been of much help to the Mueller team, ABC News reported,

Manafort was convicted by a jury in Virginia over the summer in the tax fraud and bank fraud case Mueller brought against him there. His plea deal with Mueller was announced just before a separate case Mueller brought against him in D.C. was about to go to trial.

He is set to be sentenced in the Virginia case in February, where the level of cooperation he offers Mueller could play a role in the prison time he faces. The judge in the D.C. case hasn’t set a sentencing date.