Brigham indicates that Joseph's death was a kind of blood atonement.
Brigham Young, May 6, 1877, Journal of Discourses, 26 vols. (Liverpool: Joseph F. Smith, 1877), 18:361
It is all in the hands of God. They killed Joseph, and what for? For the Gospel's sake. It was for no evil, for I was well acquainted with him. He testified to the truth, he sealed his testimony with his blood. Whether we believe in blood atonement or not, the Lord so ordered it, that Joseph, as well as others of the Prophets, sealed their testimony with their blood.