It’s unclear if Mueller will seek follow-up interviews or seek to question additional people beyond the initial batch of witnesses, but the completion of this round of questioning tracks with the goal Cobb has long stated publicly that President Donald Trump’s White House was cooperating with the Russia investigators in search of a speedy resolution to the probe.

White House attorneys have declined to name specific staffers interviewed, but sources tracking the investigation said people questioned have included former White House chief of staff Reince Priebus, presidential spokesman Sean Spicer, White House communications director and former campaign spokeswoman Hope Hicks, and current White House counsel Don McGahn.