On July 11 came the request — this time not only from Grassley but from Democrat Feinstein, too — to question the FBI's Ghattas and Rybicki. On July 27 came the Justice Department's refusal. It's likely Ghattas and Rybicki know the dossier story from the FBI's perspective
"FBI Carl Ghattas just confirmed that he has (and will share with Senate) the info fired Director Comey gave him re his talk w/ @POTUS.": Laurence Tribe Twitter account (06/27/2017)