Historian Juanita Brooks had quite the history herself. Born in 1898 and educated at both Brigham Young and Columbia Universities, she began collecting (for the Utah Historical Society) diaries and records of early Mormon settlers in the region.
She would eventually use those materials as the basis for her book The Mountain Meadows Massacre, published when she was 52. It was the first account of the tragedy using modern research techniques.
And it had a personal angle. Her grandfather Dudley Leavitt is believed to have participated in the massacre. Brooks wrote several other books before her death in 1989.