Who is in control of Congress is absolutely irrelevant to whether the U.S. Attorney for the District of Columbia returns indictments, unless you think a GOP controlled Senate (even if you regard most of the GOP Senators as "RINOs") is going to vote private bills which Trump will sign to block a prosecution he asked for, or almost as absurd that there would be enough votes in both houses of Congress to override a veto of said private bills.
@The_Reader_David What you say may be true in an IDEAL world,but we don't live in an ideal world. We live in a partisan political world,and regardless of our wishes one way or the other,Congress DOES control spending,and they DO have the authority to investigate anyone they wish,for any reason at all,or NO reason at all,other than "I wanted to". He who controls the purse strings swings a pretty damn big hammer when it comes to asking government agencies for cooperation.