This is a priority focus for Congress and law enforcemrnt. First , Flynn did nothing. Iy is not a violation of any law.
What happened here was NSA of CIA ILLEGAL wiretap without FISA warrant on a US citizen, doing his job. That is a FELONY!! This is an attempted Coup d’ Tat on our elected president by leftist traitors. Flynn quit because he made a false statement to Pense ( AND NO OTHER REASON), It makes perfect since that he was talking to his Russian Counterpart getting ready to take his position. He had no authority and spoke with no authority and everyone knew it .Trump should have REJECTED his resignation!! But in the mean time we need very a swift and strong crackdown on those insurgents in those agencies that committed these felonies to undermine our great president. I am certain we will see this very soon. Our form of government is at stake as well as the constitution of the Unites States!!
First, you have to find out who the leakers are. Based on past experience, I doubt any congressional hearing is going to get to the bottom of that.