Couple Trapped With Killer in Hidden Room With Only Roof Access

by Anonymous

I'm trying to find the title of the only old horror movie that ever game me cold chills, where a young couple moves into an apartment and the girl notices something's up.

She befriends an elderly man that's lived there for years but is reluctant to talk. She notices that a room is missing and eventually figures out by the man's blueprints that the room has been closed off. Come to find out the architect built the place so there was only roof access to the hidden room. The couple ends up trapped in the hidden room with a killer.