Flynn, a retired Army general, is a central figure in a federal investigation led by Special Counsel Robert Mueller into whether Trump aides colluded with Russia to boost his 2016 presidential campaign.

The probe has hung over the White House since January, when U.S. intelligence agencies concluded that Russia interfered in the election to try to help Trump defeat Democrat Hillary Clinton by hacking and releasing embarrassing emails and disseminating propaganda via social media to discredit her.

Russia has denied interfering in the U.S. election and Trump has said there was no collusion.

Flynn’s lawyer and a spokesman for Mueller declined to comment on Thursday.

Jay Sekulow, an attorney for Trump, said: “No one should draw the conclusion that this means anything about General Flynn cooperating against the president.”

The Times reported that Flynn’s lawyers had been sharing information with Trump’s legal team about the Mueller investigation. Citing four unnamed people involved in the case, the newspaper reported the cooperation agreement had ended.

Due to rules that aim to prevent conflicts of interest when lawyers represent clients, the move by Flynn’s lawyers to stop communicating with Trump’s lawyers indicated Flynn was now cooperating with Mueller, the Times said, although adding that in itself was not proof.

But the development has led Trump’s lawyers to believe that Flynn has begun discussions with Mueller about cooperating, according to the Times.

Flynn served 24 days as Trump’s national security adviser but was fired after it was discovered he had misrepresented his contacts with a Russian diplomat to Vice President Mike Pence.

Mueller’s inquiry is looking into Flynn’s paid work as a lobbyist for a Turkish businessman in 2016, in addition to contacts between Russian officials and Flynn and other Trump associates during and after the Nov. 8 presidential election, Reuters reported in June.

A lawyer for Flynn’s son, Michael Flynn Jr., who worked with his father and is also being investigated by Mueller, according to a person familiar with the matter, declined to comment.

Reporting by Michelle Price in Washington; Additional reporting by Roberta Rampton in West Palm Beach, Fla. and Karen Freifeld and Nathan Layne in New York; Editing by Peter Cooney