Bloomberg is reporting that the order for Michael Flynn to make contact with Russia appears to have come from the president's son-in-law, Jared Kushner. The instructions were to get foreign ambassadors and ministers to delay a UN vote condemning Israeli settlements until President Obama had left office, or to oppose the resolution altogether.
That is relevant now because one of Flynn’s lies to the FBI was when he said that he never asked Russia's ambassador to Washington, Sergey Kislyak, to delay the vote for the UN Security Council resolution. The indictment released today from the office of special prosecutor Robert Mueller describes this lie: "On or about December 22, 2016, Flynn did not ask the Russian Ambassador to delay the vote on or defeat a pending United Nations Security Council resolution."
Whether Flynn's contact with Russia was collusion or a violation of the Logan Act - a law making it illegal for a private citizen "to undermine the foreign policy of a sitting president in contact with a foreign power" - remains to be seen, but either way, it has the potential to take Kushner down as well.