The Horror!? 71: Sisters of Death (1977)

During the initiation rites for a sorority, one of the pledges is accidentally killed. Since its an old American tradition to play with guns on occasions like this, the death is ruled an accident. A few years later the surviving sisters are invited to a reunion party. Soon after they have arrived at the place where their party's supposed to be, they learn the terribly surprising truth: This party is a trap! And really, who would be suspicious if invited by persons unknown into a remote house with an electrified fence?
All this has been arranged by the dead girl's father whose conviction that one of the girls murdered his daughter on purpose has driven him mad (and induced a tendency to play the flute all night long).
I seem to have no luck with movies today. Not that Sisters of Death was terrible, it's just so terribly inconsequential. In truth, it's a little touching to see a film slink shamefully right past exploitation ("I'd really like to be titillating, but what about the children!"), mystery ("Oh, you'll never guess what I'll reveal now! Oh, you did? Well, never mind."), slasher ("Killing people is fun! What do you mean, show something!? Think about the children!") and even the slightest bit of suspense ("I don't think I should try to excite you. Think of your heart!").