Campbell mentions that Stowell handled the plates in letter to Joseph.
Martha Campbell, Letter, 19 December 1843, p. [1], The Joseph Smith Papers website, accessed August 11, 2021
. . . if I under stood him wright he [Josiah Stowell] was the firs person that took the Plates out of your hands the mor<n>ing you brough[t] them in & he observed blessed is he that seeth & believeeth & more blessed is he that believeeth without seeing & says he has seen & believeed he seems anxious to get there to renew his covenant with the Lord . . .