movie tells the incredible story of takako konishi , found frozen to death .
body was found in detroit lakes , 50 miles from fargo , in november 2001 .
policeman she met thought she had been searching for suitcase of cash .
steve buscemi 's crook buried one in the snow in 1996 coen brothers film .
rumour spread that takako , 28 , had tragically taken the tall tale to be true .
kumiko , the treasure hunter tells story of this amazing version of events .