Under questioning by panel chairman Sen. Richard Burr (R-NC), Comey said that he was uncomfortable with the unexpected meeting Lynch had with former President Bill Clinton on an airport tarmac last year. 

Comey said that meeting convinced him that the independence of the investigation was tainted with regard to the Justice Department and led him to go public with the bureau's findings on Clinton. 

When Comey testified on May 3 before the Senate Judiciary Committee, he was asked about the Lynch meeting. 

He told lawmakers "a number of things had gone on which I can’t talk about yet, that made me worry that the department leadership could not credibly complete the investigation and decline prosecution without grievous damage to the American people’s confidence in the justice system.”

http://circa.com/politics/comey-says-former-obama-ag-pressured-him-...