This Italian movie

from the 1970s probably was on channel 47 with no subtitles. I don't know any Italian, but I watched anyway, when not channel surfing. I saw this about 15-years-ago now.

The story seemed to be about a teenage male who was perhaps wanted by the police, maybe for killing someone accidentally, but maybe for something else altogether. His mother, or family, hid him in their apartment by sealing him in this room with very white walls. Alone in this sealed-off hidden room (the police would come but never seem to find the room, despite searching the house) the boy began to paint on the walls, and as the movie progressed the number of paintings increased. And that was what dragged me in, or kept me returning to that channel. These paintings were kind of haunting (or were then) done with lots of primary colors. I guess the movie company had hired a really good artist to draw what a person trapped in a room might draw, trying to recreate his lost outer world on the walls of his room.