[circlecity]

"The Democratic pair further said the Justice Department has already expressed to members of the committees that they had "serious credibility concerns" with the informant"

So, he's credible enough to use as an informant, and possibly use to get a warrant, but when he's finished and talks about his experience he has "serious credibility concerns".

[Alberta's Child]

What’s interesting is that the credibility of the guy isn’t all that important. If he gives startling testimony and his credibility is in question, then obviously the Congressional committee must see all of the records of the FBI, CIA, NSA, etc. relating to him.