I hate Barry Bonds, But what right Does Congress have Becoming the Judicial Branch!?

I mean this is Congress at it's best! It wants to Overstep into the executive branch and the Judicial as well! What kind of Bunk is it that they have "court" and p judgement look at evidence and expect the truth under oath! Barry Bonds may have Broken some law in fact But Only Politicians should be questioned By congress NOT private citizens!