Most that could be done is to question the person(s) alleged to have been there when the incident was alleged to have happened, but I think there is no legitimate reason or statute to allow for that.
My wife and I had an opposed discussion about that this morning. She thinks it is necessary for an “investigation” before Ford testifies and I was of the opinion that it would be wrong to even have Ford testify at all, with or without any investigation.
That certainly doesn’t mean I think it was impossible that Kavanaugh did such a thing, not by any means, it just means the time to have brought this to the light of day was back then, not now.