The Candy Snatchers (1973)
An innocent Catholic schoolgirl named Candy, daughter of a jewelry
store manager, is kidnapped by a trio of small time criminals who
plan on handing her back over to her family in exchange for diamonds
from the father's store. In the meantime, poor Candy is tied up,
gagged and even buried alive with only a pipe sticking out of the
ground for breathing! If the criminals don't get what they want,
they claim they'll kill her. Trouble is, Candy's father is actually
a stepfather (not to mention an adulterous sociopath!) and he's
happy she's been kidnapped because he wants her dead anyway so
he can collect a multi-million dollar insurance policy! And that's
not even half the story! (IMDB capkronos) NV