It was neither Mary Combs nor Mary Gregg. Another pair of younger George & Mary Nixon's. The suicide was Mary Ann Conner, widow of George Nixon who was the son of your people of interest, Jonah Nixon & Elizabeth Titus.
Nixon, M. A. (Mrs.) bur. 10 Jul 1889; age 75y, hung herself
--Death Records Kept by Burr W. Paxson
FindAGrave shows Mary Ann Conner Nixon, d. 8 Jul 1889, bur. Leesburg Presby
See post by Pat Duncan, 28 Mar 2003:https://www.ancestry.com/boards/SearchResults.aspx?db=mb&...