The CIA held a secret briefing for Congressional leaders regarding Russian attempts to not just influence the presidential election, but to specifically aid the election of Donald Trump. The story reports that "...In September, during a secret briefing for congressional leaders, Senate Majority Leader Mitch McConnell (R-Ky.) voiced doubts about the veracity of the intelligence, according to officials present..."
Senator McConnell has now joined a growing chorus of US elected officials calling for an investigation. President Obama has already ordered security agencies to report before he leaves office in January 2017.
President Elect Trump appears to disbelieve the security assessment. A tweet from his camp alleged that the report came from the same people who alleged WMDs in the run up to the Iraq War, over thirteen years ago. It is expected that Trump will disbelieve until he is presented with irrefutable evidence of Russian mischief.