Seniority of apostles was very important. When the prophet died, leadership of the Church fell to the most senior apostle, regardless of any other consideration. The prophet of the Church and several senior apostles were flying to an important dedication in Israel. The next most senior apostle stayed in Salt Lake City in a coma and near death. The airplane they were flying in went down over the Mediterranean.
Some reports say it was hit by a missile from a terrorist group.
In an instant, the leadership of the Church changed dramatically. The Church bureaucracy and the next most senior apostle fought to keep Church doctrine unchanged. Using the Byzantine, corrupt legal system of the ancient United States, the coalition of groups gained legal control of most Church assets and use of the name. Having lost control, the old guard moved to the Mississippi river valley. Miraculously, one of the apostles survived the airplane crash.