I have never seen anything that indicates what you have said to be true.
Read Six Seconds in Dallas.
He is correct, except for the part about being interviewed withing days. Louis Witt was tracked down by the HSCA.
You cannot read conspiracy books and get the truth, it doesn't matter how many. Most of them take great liberty with the facts, or simply repeat the accepted myths about the evidence. If you want to know the truth you must first set aside the conspiracy books and look at the evidence.
Read Six Seconds in Dallas.
A decent book, but an old one. Written before the HSCA, which debunked a lot of the misinformation that was spread about. Its author is firmly committed to a conspiracy and isn't going to let anything change his mind. :-)
Then you've never even read the Warren Report, since it is in there--and much else besides.
Google the name.
Sorry. I misspoke in my previous post. His name appears in the House Select Committee report. And I misspoke earlier when I said within days.
What happened was the umbrella man theory was brought up before the HSC and they issued an appeal--and he came forward within days.
He was a Dallas Insurance man.