Possibly "The Longest Night". Based on the true story of a young woman kidnapped and buried alive.http://www.imdb.com/title/tt0068875/
The basic idea was used in other films and TV shows like "The Screaming Woman" http://us.imdb.com/title/tt0067721/
and an episode of Quincy, M. E. I haven't found a description of the episode, but I recall that sunflower seeds or pollen lead them to place she is buried.
I suspect there are more, as the real life case got a lot of coverage in the media at the time.