WASHINGTON (Reuters) – Special Counsel Robert Mueller’s office has interviewed U.S. Deputy Attorney General Rod Rosenstein about President Donald Trump’s firing of former FBI Director James Comey, the Wall Street Journal reported on Tuesday.

Citing unnamed people familiar with the investigation, the Journal said the interview occurred in June or July. Mueller is looking into allegations of Russian meddling in the 2016 elections, possible collusion between the Trump campaign and Russia, and whether Trump may have obstructed justice by firing Comey in May.

Mueller, himself a former FBI director, ultimately reports to Rosenstein because Attorney General Jeff Sessions has recused himself from the probe.

The Journal said the handling of the interview “could be a sign that Mr. Mueller’s team doesn’t view Mr. Rosenstein as a central witness in its probe, as the deputy attorney general hasn’t withdrawn himself from overseeing it since that interview.”

The paper quoted Ian Prior, a Justice Department spokesman, as saying: “As the deputy attorney general has said numerous times, if there comes a time when he needs to recuse, he will. However, nothing has changed.”

A Justice Department spokeswoman and a representative for the special counsel both declined to comment to Reuters.

The Russian government denies any attempt to influence the election, and the Republican president has repeatedly denied any collusion, calling the investigations a “witch hunt.”