With Muller's subpoena of the bank records of Trump himself and his associates

an iron clad evidence of a giant web of money laundering, criminal conspiracy with Russian agents, and illegal coordination of election activities is about to be exposed. The frenzied activity by Republicans in Congress this week to attack Mueller and the FBI seems to be to discredit the forthcoming irrefutable evidence of law breaking by the guy sitting in the White House. The interview with Trump's lawyers next week or so seems to be a big deal and Mueller might signal to the lawyers that he is looking at a mountain of evidence of law breaking by the President and may give them the choice of either Trump resigning to save his/and his family's skin, or have Mueller present his evidence publicly to Congress and the American people---and have Trump try to survive the legal/political consequences. Flynn may have given all the evidence and corraboration Mueller needed to show that Trump himself and his team may have been actively seeking illegal aid from the Russians in wining the election, in addition to the additional crimes of money laundering, and conspiring with foreign agents, violating multiple U.S. statues.

The unusual screams of "FBI corrupt", "Justice department bad", "unfair" from Trump, Fox propaganda network, and Congressional Trump worshippers may be because they got a wind of what Mueller is about to unload.