Could that be in the original letter that Grassley does not have? If so how would the Judiciary committee aides know to interview these witnesses?
This whole thing is bizarre like false info is being put out on purpose.
They don’t want to turn over the letter as it may have exculpatory information.
It also would then subject the author and the person submitting it to a federal crime. Perjury before the U. S. Senate.
The obvious answer is that Grassley has a copy of the letter and has been playing Feinstein like a piano.