Middernacht alarm

Shortly after being made the executor of a wealthy man's estate, a man murders his benefactor. He then makes a play for the widow, who rebuffs him. To escape his arduous pursuit, she takes her little daughter on a trip but dies in an auto accident. The daughter is rescued but disappears. Her grandparents spend years looking for her, as does the executor who killed her father--if she's found she'll inherit the estate and he won't get a penny. He aims to see that she's never found, and if she is he plans to see that she doesn't live long enough to make a claim to the estate.