The Genius Bomber
Using the book, Throckmorton and Flynn figured out the recipe and method Hofmann had used for making iron gall ink that had so far defied tests for determining its age. Using a control group of non-Hofmann documents, they also noticed that unique to all Hofmann-handled documents, and to no others, were two characteristics that showed up under microscopic and video spectral compactor ultraviolet examination: ink that ran in a single direction and that cracked like alligator skin. That came from the artificial aging of homemade ink. The downward running of the ink was explained by the fact that the document was hung to dry, and once that was understood, the faint clip marks on the documents could be spotted.
To duplicate the phenomenon, Flynn made quill pens from turkey feathers, as Sillitoe and Roberts describe it, and duplicated some of the handwriting on both modern and aged paper. He oxidized the ink in an oven, and then used a fuming method on it in another sample. He found that when iron gallotannate ink was used on old paper and aged, there was no way to determine that it was not as old as might be claimed. A chemical reaction on the ink, if its on paper of the right time period, shows no difference from ink of that age. Throckmorton realized that was why so many experts had been duped.
Only two of the non-Hofmann documents showed these effects and when they asked the archivist to check the provenance, or chain of possession from collector to collector, it turned out that Hofmann had indeed sold these documents. The records had been wrong. On the 461 non-Hofmann documents examined from the same period as those purported to be, the cracking did not show up.
Worrall says that Throckmorton and Flynn examined nearly 600 Hofmann documents over a period of 16 months, and their analysis proved again and again that they could tell a Hofmann document from other documents.
Thus, the anomalies specific to many of Hofmanns documents indicated forgery. In addition, the smudges he had made to duplicate the effects of Joseph Smith's left-handed writing style had failed the test. Hofmann was right-handed, and under the microscope, his smudge marks went the wrong way.
In addition, on documents sold to the church in 1981, the ink behaved differently on different sides of a single page. That meant at least one part had been forged, written at a different time than the other. In another instance, a document that Hofmann claimed to have found pressed between the pages of an old Bible did not show the right uniformity of browning and the Bible pages did not show any acid-burning from the text, though the text had burned through the paper it was on.
A new test that tracked ions in ink to show how long it had been in contact with the paper was applied to many of the Hofmann documents. Although the aging process affected the results, the examiner concluded that none could have been dated earlier than 1920, yet all were purported to have come from an earlier time.
Still, the FBI technicians completed their extensive tests on the salamander letter and pronounced it authentic. Throckmorton was unconvinced. He believed the tests they had used were insufficient and were merely duplications of the same types of tests used before, so he redoubled his efforts to show how Hofmann had been one of the cleverest forgers in the world.
The other investigators closed in on a few other interesting pieces of evidence. They found an engraver who had made printing plates for the signatures found on several Hofmann documents, as well as a plate for the Oath of a Freeman. He even still had the photographic negatives for them all, off of which the plates were made. One had been ordered by a Mike Hansenthe same person who had purchased items used in bombs, and another by Mike Harris, but with Hofmanns unlisted home phone number. Aside from making a false copy of the Oath, it appeared that Hofmann had been raising the value of first editions by adding fake signatures.
He was clever, but not clever enough.
On one order form, signed by Mike Hansen, a fingerprint examiner had lifted a print matched to the left-hand ring finger of Mark Hofmann, tying this pseudonym conclusively to the suspect.
They also located Frances Magee, whose first husband had been a descendent of Martin Harris, the supposed author of the salamander letter. She had owned the Book of Common Prayer from which had come the handwritten poem with which Hofmann had proven that the salamander letter was authentic. There was no doubt that the handwriting in the salamander letter and the Harris poem matched. That should have been sufficient, but the investigators wanted to take one more step.