I make no claims at this point—except that I would want to see every single piece of evidence before making any claims.
Imho that is how many members of Congress will approach this matter.
If you don't believe them when they say "those documents don't contain the evidence you're looking for", then why would you believe them when they tell you they've given you "all" the documents to review? Or that they (or someone long before them) haven't already destroyed those kind of documents?