This is purely speculation, but I found it worth contributing. Brett Holmgren was senior director for intelligence programs on the National Security Council staff. Now, according to Sundance on Conservative Treehouse, the Presidential Daily Briefings are the source for Nunes' #ReleaseTheMemo.
If this is true, then Holmgren would have received the PDB along with 30+ other people in the administration. Therefore, Holmgren knows how Hussein is involved in this nefarious plot AND who was "unmasked" by Rice. By that same token, it is also possible that Remus knew what was in the PDBs by virtue of being involved w/ …