Ann Young says that Jesse Earl was killed to atone for his sins.
Ann Eliza Young, Wife No.19, or, The story of a life in bondage : being a complete exposé of Mormonism, and revealing the sorrows, sacrifices and sufferings of women in polygamy (Hartford, CT: Dustin, Gilman, & Co. 1876), 196
Another victim to the Blood-Atonement was a young man named Jesse Earl, a musician of rare talent and great promise. He was a very intimate friend of the Prophet's oldest son, Joseph, and had lived a great deal in the Prophet's family. The reason of his death has never been given; it was only said that his sins were past forgiveness, except his blood should atone for them.