Newhall reports hearing Hyrum publicly testify of the Book of Mormon.
J. B. Newhall, Statement, Salem Advertizer and Argus, rep. in Times and Seasons 4, no. 15 (June 15, 1843): 234–235
We have seen Hiram Smith, a brother of Joseph's and heard him preach, and conversed with him about his religion, its origin and progress; and we heard him declare, in this city in public, that what is recorded about the plates, &c. &c., is God's solemn truth.