Context: Grassley was talking about making sure the FBI properly and fairly investigated allegations, whether they were true, even if they turned out to be false.
It was a positive statement, calling on the FBI to be fair, even if the outcome was favorable for Biden.
Unlike this out of context snippet of a quote.
@volkris @GAPoliticalJunkie from the snippets of context I can find online you appear to be incorrect. Grassley is not talking about the investigation he is demanding the release of a document that appears to implicate Biden without regard to whether the document is truthful or fictitious.