Robert Mueller's investigators interviewed Rod Rosenstein, who is overseeing the Russia investigation

Robert Mueller’s investigative team interviewed Deputy Attorney General Rod Rosenstein as part of their ongoing investigation into possible collusion between the Trump campaign and Russian operatives.

A report from The Wall Street Journal on Tuesday night cited people familiar with the investigation who said the interview took place in June or July, not long after Rosenstein appointed Mueller as the special counsel in charge of the investigation.

Rosenstein made that move after President Donald Trump admitted that firing former FBI Director James Comey, who had been leading the Russia investigation, had taken “great pressure” off of him.

Former federal prosecutor Peter Zeidenberg told The Journal that it was “unusual” for Mueller’s team to sit down with Rosenstein given his oversight of Mueller’s team’s activities. Zeidenberg said the move could indicate that Rosenstein is not considered to be a key witness in the Russia probe. If he were, Rosenstein may have been forced to recuse himself from Russia-related investigative matters — just as Attorney General Jeff Sessions did earlier this year.

Justice Department spokesman Ian Prior reiterated Rosenstein’s previous assertion that he would recuse himself from the Russia investigation if necessary, but added that as of now, “nothing has changed.”

Zeidenberg suggested that Rosenstein’s testimony to Mueller’s investigators “either isn’t that critical or there are other people that could say the same thing.”

Mueller’s investigation has taken several dramatic turns in recent months, in which multiple people inside and outside the Trump campaign have caught the special counsel’s attention. Several of Trump’s closest associates and immediate family have retained personal attorneys as a result.

The probe includes a concerted effort to reel in Trump’s former campaign chairman Paul Manafort, his former national security adviser Michael Flynn, and his senior White House adviser and son-in-law, Jared Kushner.

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.