trump & Co. are the most likely source that mailed them to Johnston, a known regular on Maddow's MSNBC show. The why isn't too bloody hard to figure out.
The narcissist in chief has been taking a shit load of heat the last week or so for his comments about being wiretapped, his ties to unsavory types via Deutsche Bank, the flack over the failed Repeal & Replacement of the ACA, etc, etc! Light a candle under new and juicy item to change the news driven narrative and, voilà , the heat is removed from those issues.
That tactic also gets poor put upon trump sympathy from his sycophantic lemmings, sheep and assorted ass kissers coming to his defense, the ******* creatures! Nothing new to see in trump's shtick!