This is very well researched, and one of those..."they didn't ever teach this in Sunday-school" moments.
This 2 part series covers how Brigham seized control of the church and made sure he stayed in control. Also discusses the "mysterious" death of Samual Smith shortly after Joseph and Hyrum were murdered.
https://youtu.be/9BMoPpEtJV4
https://youtu.be/AMVoa_uG5Vs