A film shown at the Flaherty Film Seminar in 1986 may fit this category.  A
MAN LISTED TO DIE (sorry, that's the best translation of the Portuguese),
a.k.a.  TWENTY YEARS LATER in U.S.  distribution, by Edwardo Coutinho, began
as a left-wing propoganda feature on a farm workers' organizer murdered by
the landlords, "staring" the man's wife, who had become something of a
peasant heroine.  The film ran into various problems, including a right-wing
coup in 1964; Coutinho returned to the project in 1981 after a civilian
government returned.
 
C.  had hidden the original negative and used it in the later film, which
centers on three elements: the original dramatic footage; the organizer's
murder, the political and police reactions, and the wife's rise to
prominence, traced in newspaper headlines and interviews; and a search for
the participants in the original film, including the wife, who had gone into
hiding and hadn't seen her family or friends for 17 years.
 
Showing the original footage to the original participants give a means of
comparing attitudes then and now; some of the changes were quite remarkable.
But searching for and finding the wife, and then locating her eight children
who had been scattered among relatives and friends and contrasting their
situation then with their lives and attitudes later, is the heart of the
film.
 
And raised considerable discussion about invasion of privacy and the role of
the producer and film crew in the search process.  It was a provocative
example of how to re-examine a social event for which important graphics
material--the original footage, old newsreels, newspaper pictures and
stories--still exists.  One of the better experiences of that Seminar.
 
PJO