Latona tells us WTF happened:
Mr. LATONA. …After that had been determined, I then proceeded to completely process the entire rifle, to see if there were any other prints of any significance or value any prints of value--I would not know what the significance would be, but to see if there were any other prints. I completely covered the rifle. I also had a firearms man----
Representative BOGGS. What do you cover it with?
Mr. LATONA. Gray fingerprint powder.
Representative BOGGS. What is that powder?
Mr. LATONA. It is usually a combination of chalk and mercury, or possibly white lead and a little bit of resin material to give it some weight.
Mr. EISENBERG. And you testified earlier that that adheres----
Mr. LATONA. To the moisture that was left by the finger, the fingers or the hands, when it came in contact with the surface.
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Mr. LATONA. This particular weapon here, first of all, in my opinion, the metal is very poorly finished. It is absorbent. Believe it or not, there is a certain amount of absorption into this metal itself. It is not finished in the sense that it is highly polished.
Representative BOGGS. So this would be conducive to getting a good print, or would it?
Mr. LATONA. It would not.
Representative BOGGS. I see---because it would absorb the moisture.
Mr. LATONA. That's right.
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Mr. EISENBERG. …Mr. Latona, you were saying that you had worked over that rifle by applying a gray powder to it. Did you develop any fingerprints?
Mr. LATONA. I was not successful in developing any prints at all on the weapon. I also had one of the firearms examiners dismantle the weapon and I processed the complete weapon, all parts, everything else. And no latent prints of value were developed.
Mr. EISENBERG. Does that include the clip?
Mr. LATONA. That included the clip, that included the bolt, it included the underside of the barrel which is covered by the stock.
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Mr. EISENBERG. I now hand you a small white card marked with certain initials and with a date, "11-22-63." There is a cellophane wrapping, cellophane tape across this card with what appears to be a fingerprint underneath it, and the handwriting underneath that tape is "off underside of gun barrel near end of foregrip C 2766," which I might remark parenthetically is the serial number of Exhibit 139. I ask you whether you are familiar with this item which I hand you, this card?
Mr. LATONA. Yes; I am familiar with this particular exhibit.
Mr. EISENBERG. Can you describe to us what that exhibit consists of, that item rather?
Mr. LATONA. This exhibit Or this item is a lift of a latent palmprint which was evidently developed with black powder.
Mr. EISENBERG. And when did you receive this item?
Mr. LATONA. I received this item November 29, 1963.
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Mr. EISENBERG. Did you succeed in making identification?
Mr. LATONA. On the basis of my comparison, I did effect an identification.
Mr. EISENBERG. And whose print was that, Mr. Latona?
Mr. LATONA. The palmprint which appears on the lift was identified by me as the right palmprint of Lee Harvey Oswald.
Mr. EISENBERG. Now, Mr. Latona, as I understand it, on November 23, therefore, the FBI had not succeeded in making an identification of a fingerprint or palmprint on the rifle, but several days later by virtue of the receipt of this lift, which did not come with the weapon originally, the FBI did succeed in identifying a print on Exhibit 139?
Mr. LATONA. That is right.
Mr. EISENBERG. Which may explain any inconsistent or apparently inconsistent statements, which I believe appeared in the press, as to an identification?
Mr. LATONA. We had no personal knowledge of any palmprint having been developed on the rifle. The only prints that we knew of were the fragmentary prints which I previously pointed out had been indicated by the cellophane on the trigger guard. There was no indication on this rifle as to the existence of any other prints. This print which indicates it came from the underside of the gun barrel, evidently the lifting had been so complete that there was nothing left to show any marking on the gun itself as to the existence of such even an attempt on the part of anyone else to process the rifle.
Mr. DULLES. Do I understand then that if there is a lifting of this kind, that it may obliterate----
Mr. LATONA. Completely.
Mr. DULLES. The original print?
Mr. LATONA. That is right.
Mr. EISENBERG. So that you personally, Mr. Latona, did not know anything about a print being on the rifle which was identifiable until you received, actually received the lift, Exhibit 637?
Mr. LATONA. On the 29th of November.
Here is a theory that makes sense to me:
It appears to me that Latona (with no cellophane or any other indication that there was any kind of print, or remnants of a print, underneath the wood of the fore stock) did not see the faint remnants that Day said were left on the barrel. And Latona subsequently covered the entire gun with gray powder. The remnants that Day indicated was still on the underside of the barrel lacked enough moisture (due to the black powder’s absorbency) to adhere to the gray powder. And therefore no useable print was developed.
I believe that Day did nothing wrong except verbally relying on Drain to notify the FBI lab about the palm print (I believe that he should have documented it in writing or indicated it in some way on the rifle). The DPD had jurisdiction of the case on 11/22/63, the FBI did not have jurisdiction. Unless Day had been specifically instructed to turn over the palm print lift (he said he had not), Under the circumstances, I think it would have been wrong for Day to turn over any evidence that he had not specifically been instructed to turn over.