After arriving in Salt Lake City, the Baker–Fancher party made their way south along the Mormon Road, eventually stopping to rest at Mountain Meadows.

[3][4][5] Acting on rumors of hostile behavior on the part of the travelers, local Mormon militia leaders, including Isaac C. Haight and John D. Lee, made plans to attack them as they camped at the meadow.

The leaders of the militia, wanting to give the impression of tribal hostilities, persuaded Southern Paiutes to join with a larger party of militiamen disguised as Native Americans in an attack on the wagon train.

Eventually, fear spread among the militia's leaders that some immigrants had caught sight of the white men, likely discerning the actual identity of a majority of the attackers.

By this time, the travelers were running low on water and provisions, and allowed some members of the militia – who approached under a white flag – to enter their camp.

Scholars debate whether senior leadership in the LDS Church, including Brigham Young, directly instigated the massacre or if responsibility for it lay only with the leaders of the militia.

U.S. President James Buchanan had recently issued an order to send federal troops to Utah, which led to rumors being spread in the territory about its motives.

[10] The Baker–Fancher party was refused provisions in Salt Lake City and chose to leave there and take the Old Spanish Trail, which passed through southern Utah.

They had traveled the 165 miles (266 km) south from Salt Lake City, and Jacob Hamblin suggested that the wagon train continue on the trail and rest their cattle at Mountain Meadows, which had good pasture and was adjacent to his homestead.

He recorded Hamblin's account that the train was alleged to have poisoned a spring near Corn Creek, resulting in the deaths of eighteen cows and two or three people who ate the contaminated meat.

Carleton invited readers to consider a potential explanation for the rumors of misdeeds, noting the general atmosphere of distrust among Mormons for strangers at the time, and that some locals appeared jealous of the Fancher party's wealth.

[15] The Baker–Fancher party left Corn Creek and continued the 125 miles (201 km) to Mountain Meadows, passing Parowan and Cedar City, southern Utah communities led respectively by Stake Presidents William H. Dame and Isaac C. Haight.

[17] As the party approached, several meetings were held in Cedar City and nearby Parowan by local LDS Church leaders pondering how to implement Young's declaration of martial law.

[18] On the afternoon of Sunday, September 6, Haight held his weekly Stake High Council meeting after church services and brought up the issue of what to do with the immigrants.

[19] The Council resolved to take no action until Haight sent a rider, James Haslam,[20]: 3437  out the next day to carry an express to Salt Lake City (a six-day round trip on horseback) for Young's advice, as Utah did not yet have a telegraph system.

[21]: 157 The dispirited Baker–Fancher party found water and fresh grazing for its livestock after reaching grassy, mountain-ringed Mountain Meadows, a widely known stopover on the old Spanish Trail, in early September.

[21]: 174, 178–180 On Friday, September 11, 1857, two militiamen approached the Baker–Fancher party wagons with a white flag and were soon followed by Indian Agent and militia officer John D. Lee.

Under Mormon protection, the wagon-train members would be escorted safely back to Cedar City, 36 miles (58 km) away, in exchange for turning all of their livestock and supplies over to the Native Americans.

[34]: 250 [35] Leonard J. Arrington, founder of the Mormon History Association, reports that Brigham Young received the rider, James Haslam, at his office on the same day.

When he learned what was contemplated by the militia leaders in Parowan and Cedar City, he sent back a letter stating the Baker–Fancher party was not to be meddled with, and should be allowed to go in peace (although he acknowledged the Native Americans would likely "do as they pleased").

[39][40] In Carleton's investigation, at Mountain Meadows he found women's hair tangled in sage brush and the bones of children still in their mothers' arms.

[74] The first detailed and comprehensive work using modern historical methods was The Mountain Meadows Massacre in 1950 by Juanita Brooks, a Mormon scholar who lived near the area in southern Utah.

"[98] Mormon leaders immediately proclaimed Pratt as another martyr,[99][100] with Brigham Young stating, "Nothing has happened so hard to reconcile my mind to since the death of Joseph."

[112][113] Col. William H. Dame, the ranking officer in southern Utah who ordered the Mountain Meadows massacre, received a patriarchal blessing in 1854 that he would "be called to act at the head of a portion of thy Brethren and of the Lamanites (Native Americans) in the redemption of Zion and the avenging of the blood of the prophets upon them that dwell on the earth".

From July to September 1857, Mormon leaders and their followers prepared for a siege that could have ended up similar to the seven-year Bleeding Kansas problem occurring at the time.

He met with many of the eventual participants in the massacre, including W. H. Dame, Isaac Haight, John D. Lee and Chief Jackson, leader of a band of Paiutes.

When Smith returned to Salt Lake, Brigham Young met with these leaders on September 1, 1857, and encouraged them to fight against the Americans in the anticipated clash with the U.S. Army.

However, in Young's only known correspondence prior to the massacre, he told the Church leaders in Cedar City: In regard to emigration trains passing through our settlements, we must not interfere with them until they are first notified to keep away.

"[130] MacKinnon suggests that hostilities could have been avoided if Young had traveled east to Washington D.C. to resolve governmental problems instead of taking a five-week trip north on the eve of the Utah War for church-related reasons.

Approximately 400 people, including many descendants of those slain at Mountain Meadows and Elder Henry B. Eyring of the LDS Church's Quorum of the Twelve Apostles attended this ceremony.