Flynn has been picked as President Trump's national security adviser.
The conversation that was intercepted took place late December after Obama announced sanctions against Russia and kicked out 35 diplomats in response to what he believed was their meddling in our presidential election campaign.
Flynn had been under investigation for the last five months in a broader probe of possible ties of the Trump campaign with Russia--this is ongoing.
That investigation involves the FBI, CIA, NSA and Treasury Department.
Ironically, Hillary Clinton was found to have an illegal private server that was very likely hacked by unfriendly governments, and had sent classified emails to Sid Blumenthal, a non-government person, and she has not been indicted for any of this.