http://www.motherjones.com/politics/2017/02/why-michael-flynn-still-needs-to-be-investigated-russia
"But Flynn had pulled a dumb move, for, as he should have known, US intelligence was intercepting the communications of Kislyak, and transcripts of their chats indicated Flynn and the Russian had indeed talked about the sanctions. And these transcripts were shared among various US government agencies. Before Trump fired acting Attorney General Sally Yates for not enforcing his Muslim travel ban, last month she warned the Trump White House that Flynn had misrepresented the calls and was therefore vulnerable to Russian blackmail. That warning was enough reason for Trump to boot Flynn, but he did not. It took the increasing criticism of Flynn and the mounting calls for an investigation of recent days for the White House to request that Flynn find another perch for his anti-Islam crusade. Flynn's departure should not end the demands for an investigation. One tantalizing and somewhat overlooked aspect of the Post story that did him in was the fact that Flynn hobnobbed with Kislyak during the campaign. The paper reported that the Flynn-Kislyak conversations "were part of a series of contacts between Flynn and Kislyak that began before the Nov. 8 election and continued during the transition, officials said." And the paper noted, "Kislyak said that he had been in contact with Flynn since before the election, but declined to answer questions about the subjects they discussed." This is the mystery that now needs an answer: What was Flynn talking about with the Russians during the campaign?"