I was too young to see it, but I remember a movie being advertised in the mid 70s that was a horror movie. I think the idea was that one person (likely a child) was evil and killing off his relatives. In the trailer they showed one person being sealed in a room, with voice over saying he (the villain) gave them (the victim) a room of his own and another scene where 2 people are crushed together in a shower. Any ideas?
nothing springing to mind... I guess PSYCHIC KILLER ticks a few of those boxes. not child though.
I was wondering if this was ARNOLD from 1973?
https://www.youtube.com/watch?v=I49SGOurZTw
The "room of his own" and "the crushed in a shower" scenes are in this trailer.