On October 15, 1985, in Salt Lake City, Utah, two pipe bombs exploded. One killed businessman and Mormon bishop Steve Christensen, and the other killed a grandmother, Kathy Sheets. The package that killed Sheets was addressed to her husband, Gary, who also was a bishop in the Mormon Church. The next day, a third bomb exploded in the car of Mark Hofmann.
Hofmann, who survived the blast, told police that he had seen a strange package sitting in his car, and when he reached for it, it exploded. Bomb investigators knew immediately that Hofmann was lying: Evidence indicated that Hofmann had been kneeling in the seat of the car, apparently working with the bomb, when it detonated. Hofmann leaped to the top of the suspect list in the other bombings.
As the investigation progressed, police discovered that Hofmann was somewhat of a whiz at locating ancient documents and had sold many historical documents to the Mormon Church. However, they also uncovered evidence that the documents actually were forgeries, thus raising suspicion that Hofmann planted the bombs in an attempt to cover his forgeries.
The case ended when the police confronted Hofmann with evidence that proved he had forged his discoveries. Document examiners George J. Throckmorton and William Flynn discovered several things amiss when examining a 17th century document Hoffman had uncovered. Letters with tails, or descenders, such as Y and J, seemed to overlap with taller letters, such as L and T, when the former appeared in lines above the latter. That kind of overlapping wasn't possible with the handset type that was used to make the original documents in the 17th century.
The examiners also noted the alligator effect — cracking and breaking of the ink from the use of chemical oxidants that were applied to artificially age the appearance of the ink. Natural aging doesn't produce such changes.
Hofmann confessed to the bombings and the forgeries in exchange for a life sentence. He also told investigators how he pulled off the forgeries, which were so realistic that many experts had deemed them authentic.