The Nauvoo Expositor was a newspaper in Nauvoo, Illinois, that published only one issue, on June 7, 1844. Its publication set off a chain of events that led to the death of Latter Day Saint prophet Joseph Smith.

The Expositor was founded by several seceders from the Church of Jesus Christ of Latter Day Saints and some non-Mormons in the Nauvoo area. The single edition of the newspaper was critical of Smith and other church leaders. Specifically, Smith was criticized for teaching doctrines such as plural marriage and exaltation.

In response to the newspaper’s publication, Smith and the Nauvoo City Council declared the paper a public nuisance, and ordered the press destroyed. The town marshal carried out the order during the evening of June 10.[footnote]Nauvoo Expositor – Wikipedia[/footnote]

The order Joseph Smith gave for the destruction of the printing press:[footnote]History of the Church, vol. 6, page 448[/footnote]

To the Marshall of said City, greeting.
You are here commanded to destroy the printing press from whence issues the Nauvoo Expositor, and pi the type of said printing establishment; and if any resistance be offered to your execution of this order by the owners or others, demolish the house; and if anyone threatens you or the Mayor or the officers of the city, arrest who threaten you, and fail not to execute this order without delay, and make due return hereon.

By Order of the City Council,
Joseph Smith, Mayor 

Interestingly enough though the single paper printed by the Expositor was critical, most all of the claims in the publication were accurate.[footnote]Defending the Expositor: On Penalty of Death… – Thoughts on Things and Stuff[/footnote]

Crash Course:

The Navoo Expositor single publication
The Nauvoo Expositor – Mormon Think
Defending the Expositor: On Penalty of Death… – Thoughts on Things and Stuff