MOUNTAIN MEADOWS, Washington County — Nearly 150 years after scores of unarmed men, women and children were massacred here, the collective guilt still remains palpable enough among area residents that vandals regularly seek to alter the history laid out on memorial markers.

So it was in the spirit of truth-telling and frankness that LDS Church historians led dozens of people to the monument on Monday, laying out in minute detail how men who had devoted their lives to God laid a plan and carried out the Mountain Meadows Massacre on Sept. 11, 1857.

The premeditated slaughter of 120 people that day was so horrific that many in southern Utah — some of whose ancestors participated in the killing — refuse to talk about the events to this day.

Historian Richard Turley acknowledged the "collective burden they have carried for many, many years," detailing how Issac C. Haight — then the mayor of Cedar City and the stake president of the LDS Church there — spearheaded a drive to kill the Arkansas immigrants.

He and others schemed to involve Paiute Indians so the killing could later be blamed on them. A few Paiutes were involved at some point, Turley said, but it is clear from the evidence that "white men did most of the killing."

Turley, director of the Family and Church History Department of The Church of Jesus Christ of Latter-day Saints, and two historian colleagues have spent the past several years researching and writing what will become the LDS faith's official account of what happened that fateful day. Their efforts have been enhanced by several other researchers who also helped seek out information from across the country.

The book is now with Oxford University Press, and the authors hope to have "Tragedy at Mountain Meadows" published by year's end.

"We hope by looking at these events squarely in the face that we can bring details" of the massacre to light so the descendants "don't have to labor under that sense of collective guilt any more," Turley said. The events have been clouded in controversy for decades, and several different writers have pieced together various versions of what happened and published books about the event.

Some — including local historian Will Bagley — have placed the blame squarely on then-church president Brigham Young, who Turley said did send letters to leaders in southern Utah in the months before the massacre — as federal troops were approaching the state — warning of interlopers who may cause harm and urging the LDS faithful to defend themselves.