Question

psycho killer horror suspense thriller about a killer who turns the power off to a house and rigs the fuse box so that the boyfriend gets electrocuted while the girlfriend watches. She then locks herself in the house so the killer burns the house down. Made before 1982 shown on HBO in the daytime so probably rated PG. The killer also had some kind of problem with his mother like these horror movies do. The only other scene I remember is a girl discovering what his problem was (or seeing his mother when he was with her). He sees her, she runs away down the stairs while he slowly walks after her, she gets to the back kitchen door only to realize that a board is propped against the doorknob outside. Meanwhile the killer is slowly descending the stairs until he reaches the bottom. The girl breaks the glass finally realizing it's blocked and pushes the board away. Then there's a long shot of the girl running away between two rows of trees. Also, the killer wears a trench coat and fedora hat I think. It seems like you never really see his face. I know it's not "Don't Go in the House" or "Boogeyman."