Mueller’s team issued more than 2,800 subpoenas, executed nearly 500 search warrants and interviewed more than 500 witnesses. That means the special counsel likely compiled thousands, if not millions, of documents and pieces of evidence. Material collected ranges from a $15,000 ostrich jacket worn by President Donald Trump’s former campaign chairman to emails and encrypted text messages to hard drives and laptops. It could even include tax returns, if Mueller sought them.

In one Mueller case, that of longtime Trump confidant Roger Stone , the government said it had turned over 9 terabytes of discovery — an amount so large that Stone’s lawyers said if it were on paper, it would pile as high as the Washington Monument, twice.

If all of that was delivered to Congress, the House Judiciary Committee might need to invest in a larger office space. But lawmakers say what they really want is documentation of everything — and an idea of how that evidence guided Mueller’s conclusions.