Well, you be your own judge, poster j-mac, but for me......I've noted how the Committee has mostly relied upon long time loyal Republicans. Not a few of which worked directly for Don Trump, or in the case Hutchinson was a 'special assistant to the President', in addition to reporting directly to Mark Meadows And notably, her office was just steps from the Oval.
If the Committee was not on the "up and up".....they would have brought in a passel of Dems who had axes to grind. Instead, they have provided sober-sided long established and credentialed Republican operatives or supporters.
Also, lending credibility to them is that witnesses are corroborating other's testimony. In short, the testimony is consistent and validating other testimonies.
Also, lending credibility in my narrow parochial view is that this Committee, made up of Republicans and Democrats, has been markedly restrained --for a televised Congressional hearing -- in their opinionizing and side-bars. These folks seem to be a pretty conservative group of investigators. And are projecting an air of 'just-the-fact-Ma'am'.
I like that. It inspires confidence that these folks truly want to get to the bottom of things.