Mild, but enjoyable kinda proto-slasher thriller

Made for TV giallo-ish/slasher-ish horror/thriller/mystery movie. An elderly man believes his second wife is trying to poison him. He instructs his daughter to summon her three sisters (from whom he is estranged) to the family farm so he can tell them what's going on. The three reluctantly attend (their arrival coinciding with the mother of all thunderstorms, which continues throughout the movie), only to start getting bumped off by a mysterious figure dressed in a yellow hooded rain coat, carrying a pitchfork.

It plays out a little like 'Ten Little Indians meets I Know What You Did Last Summer'. The featured cast is strong on paper (Sally Field, Eleanor Parker, Julie Harris, Jessica Walter, Jill Haworth and Walter Brennan; two Oscar winners and two Oscar nominees in that lot!), but for some reason the acting by everybody is way over the top. Directed by John L Moxey (who did the Kolchak TV movie The Night Stalker the same year), and written by Joseph Stefano, best known for his screenplay for Hitchcock's Psycho. Given the year this was made and the medium it was made for it's pretty tame, but it's got plenty of atmosphere and that wonderful '70s feel'. 6/10.