Mormon Church Historian Marlin K. Jensen has informed descendants of the massacre that left 120 people dead a century and a half ago that his church will seek National Historic Landmark designation of its holdings at the Mountain Meadows site in southern Utah.

“A National Historic Landmark designation, along with the continued efforts of the church and descendants groups, will ensure that those who died at Mountain Meadows will always be remembered as part of our nation’s history,” said Jensen, the historian of the Church of Jesus Christ of Latter-day Saints, at a Friday meeting with descendants in Carrollton, Ark.

At a September memorial service at the grave site, marking the deaths that occurred 150 years ago on Sept. 11, 1857, church leader Henry B. Eyring said: “What was done here long ago by members of our church represents a terrible and inexcusable departure from Christian teaching and conduct.”

In addition to seeking a greater historical designation, the church recently bought 600 acres of land at the site to prevent it from being developed into a residential subdivision.