Republicans control all three branches of government
Barack Obama, a Democrat, was the President and in control of the Executive Branch during the investigation.
You can have as many investigations as you want. Double jeopardy only applies to actual trials. If a crime was really committed, it would seem terrible negligence to fail to investigate. Right now, in 2017, while Hillary has no influence anywhere over anyone. But why isn’t it happening? Do you think Trump is covering up for Hillary? What does she have on him? He promised to investigate her, has the power to investigate her, has a slam-dunk case according to you, and yet he isn’t doing it. Hmm. What about Gowdy? Why did he suddenly stop investigating the moment Hillary lost? The very moment her ability to wield her awesome government power for evil was lost, he just gave up and said nevermind, I guess there was nothing to see here after all! He always seemed to be in the tank for Hillary. I smell conspiracy.
Either that or show trial, they smell very much alike.