They eventually shot between 40 and 100 Native American men and one woman with guns and a cannon during the siege and subsequent pursuit, capture, and execution of the two groups that fled during the last night.

[14]: 276  The bodies of up to 50 Timpanogos men were beheaded by some of the settlers and their heads put on display at the fort as a warning to the mostly women and children prisoners inside.

[16] Before the massacre the Timpanogos people initially tolerated the new presence of the settlers from the Church of Jesus Christ of Latter-day Saints (LDS Church) who had only recently begun moving south into Utah Valley in the past year from the main settlement in the Salt Lake Valley.

Isaac Higbee, Parley P. Pratt and Willard Richards convinced Brigham Young to exterminate any Timpanogos hostile to the Mormon settlement.

[20] Young sent the Nauvoo Legion down with Captain George D. Grant and later sent General Daniel H. Wells to lead the army.

Little Chief said that Roman Nose and Blue Shirt were great thieves who had decided to live off of the settlers' cattle all winter.

[citation needed] Captain John Scott took fifty men into Utah Valley to put a "final end" to the "depredations.".

[22] As the settlers tried to move into the valley, they were actively blocked by a group of Timpanogos led by An-kar-tewets with warnings that trespassing would be met with death.

[15][3]: 65 The settlers built a stockade called Fort Utah and armed it with a twelve-pound cannon to intimidate the Timpanogos.

[3]: 64–65  They also built several log houses, surrounded by a tall 14-foot (4.3 m) palisade 330 by 165 feet [101 by 50 m],[12]: 84  with gates in the east and west ends, and an elevated middle deck for the cannon.

[3]: 67 The fort was built on the sacred grounds for the annual fish festival and very close to the main Timpanogos village on the Provo River.

[21][24]: 23 [25] The new presence of settlers also exposed the longtime residents of Utah Valley to measles, and they began dying in large numbers.

[21] In August, a Timpanog named Old Bishop was murdered by Rufus Stoddard, Richard Ivie, and Gerome Zabrisky over a shirt they wanted from him.

[3]: 67–68 [21][26] Another account from Thomas Orr states that the Timpanogos agreed not to take the settlers' cattle if they would not kill their wild game.

In October, apostle Charles C. Rich negotiated a peace treaty, and Brigham Young again advised Fort Utah not to hold the Timpanogos as equals, but to "have dominion" over them.

[3]: 70 [17]: 137  By January 1850, settlers of Fort Utah reported to officials in Salt Lake City that the situation was getting dangerous.

[19] Young was also concerned that losing Fort Utah would disrupt his plans to settle other fertile valleys and have a route to California.

Stansbury had also been a victim of cattle theft and supported Young's decision to go to war by providing supplies and the services of his physician.

Some Timpanogos who were friends with some of the settlers sought shelter in Fort Utah before the battle, including Antonga, whom the Mormons called "Black Hawk".

[12]: 178  The next day, the soldiers mounted shields on sledges and the defending Timpanogos suffered about ten casualties and Chief Opecarry was wounded.

[15]: 105  Black Hawk was sent by the militia to scout out the village the next morning, and it was deserted except for the bodies of around ten Native American people shots by the Nauvoo Legion.

[15]: 105  Ope-carry, Patsowet, and their families: six women and seven children, managed to flee over the mountains using snowshoes they made in the canyon.

They were supposed to be shipped to Salt Lake, but they were held up to be displayed in front of the prisoners at Fort Utah as a warning.

[15]: 106  More than forty prisoners, mostly women and children,[14]: 276  were taken and placed with Mormon families "as servants" in Salt Lake City "for the purpose of weaning them from their savage pursuits, and bringing them up in the habits of civilized and Christian life".

[3]: 77 [39] News of the enslavement reached the US Government, and became one of the first priorities of Edward Cooper after he was appointed as Indian Agent of Utah later that year.

[41] Resentment by the Indians over the incident towards the Latter-day Saints became intense in the years following and was a factor contributing to Wakara's War that took place from 1853-1854.

The United States Congress did not ratify the treaty however, leading to death and starvation when promised provisions did not arrive as Utes were forced to winter in Strawberry Valley in 1867 while en-route to what would become the Uintah and Ouray Indian Reservation.