The GOP exists to never get to the bottom of anything.
I think these two Congressmen want to find out the truth—but they need to forget everything they think they know and start from scratch—as you always should do when beginning any investigation.
Collect the data—ignore all narratives—and see where the data leads you.
There is nothing wrong with getting it wrong along the way—as long as you are able to change views when there is persuasive information contradicting your views.