I think he means the partial palmprint on an index card that showed up in Washington a week after the assassination.
No, that's not correct..... The index card was listed as item #14 on the evidence list that listed the items of evidence that was released to the FBI at midnight Friday, 11 / 22/ 63. It is listed as " Partial palm print off underside of gun barrel near end of foregrip " ( The quotation marks are on the document , which indicates the typist copied those words off the index card)Both Captain Doughty and who released the card and FBI agent Vince Drain who received that index card initialed the card at the time.
So the index card was in Washington on Saturday 11 / 23 /63....... Any other story about that card is BS......