Here the 1837 edition changed hath to has. The 1852 LDS edition restored the original hath but did so unintentionally, it would seem, since nearly all instances of Joseph Smith’s grammatical emendation of the archaic -(e)th ending to -(e)s for the 1837 edition have been maintained in the text. For a few other examples like this one here in Helaman 9:20 (that is, where the original hath was restored in some later edition), see under Alma 34:8. The critical text will, of course, restore or maintain, as the case may be, each original instance of the archaic inflectional ending -(e)th. For a complete discussion of this editing, see under infl al endings in volume 3.
Summary: Maintain the original hath in Helaman 9:20 since this is how the earliest text reads: “who is this man that hath done this murder”.