Hofmann created the infamous Salamander Letter and other forged documents, which he claimed to have found using a "proprietary system". He sold these documents as a document dealer for profit. A number of these documents purported to detail the origin of the Church of Jesus Christ of Latter-day Saints (LDS Church; see also Mormon), which the church officials then purchased - some claim to hide embarassing history about the religion. His last announcement was his discovery of a copy of the long-vanished 17th-century printed broadside "Oath of a Freeman."
Then on November 15, 1985, two mail bombs exploded in Salt Lake City, Utah, killing two people. The next day a pipe bomb exploded in Hofmann's car, wounding him. The victim of the first bombing had been pressuring Hofman to complete a deal which was a con that Hofmann could not pull off. The victim of the second bombing was a diversion to take suspicion away from Hofmann. In investigating the bombings, the police discovered Hofmann's studio, and other inciminating evidence. He was arrested for the murders and forgery that following February. He later pleaded guilty to lesser related charges to avoid the death penalty, and was sentenced to life in prison.
During his career Mark Hofmann fooled some very renowned people. Among them was Daniel Lombardo, a curator for a library in material written by Emily Dickinson. Hofmann sold him a "newly discovered" manuscript copy of an unpublished Dickinson poem for twenty four thousand dollars, which was later determined to be a fake. Lombardo later remarked that "Hofmann was one of the most skilled forgers in this century. The lengths he went to fool all the experts were extraordinary."
It is also worth noting that some of Mark Hofmann's "discoveries" were presented to one of the top document experts in the United States; this expert pronounced the forged documents as consistent with the claimed origin.