I doubt if he was bribed. Blackmailed, possibily. He’d be screwed - he wouldn’t be able to go to the FBI, because Holder would have been in on it!
Maybe is Obama loses the election, Roberts will be able to get the FBI involved.
Unlikely. If he was blackmailed it was probably over something he would want nobody else to know about which is why he was blackmailed to begin with (that is, IF he was blackmailed)