Wn Nelson Howden die 24 Jun 1980 Unknown ????

What has happen to William Nelson Howden born 1985 Oakleigh Vic / Died 24 Jun 1980 place unknown , buried unknown along with his wife Amy Beatrice Howden nee Crome again born 1883 Armadale Vic / died 20 Dec 1979 place unknown, buried 21 Dec 1979 again place unknown, so a big question is what has happen to these two people, there must be some records around, as to what has happen to them please. someone must know????