It's about a boy who pretends to be blind so he can spy on people through a spyglass.
This is what I remember:
In a distant town the construction of the train tracks will begin, so an engineer gets to know the town, staying in the only hotel in town run by a girl, who has a younger brother who pretends to be blind to spy on the habitants.
From the attic he spies with a spyglass, so he sees the mayor of the town, disguised as a deer, and his secretary following him in a role play.
Someone kills the mayor by mistaking him for a real deer, all this seen by the boy from the attic.
The engineer is flagged as a suspect and sent to jail.
from here I do not remember more.
P.S. There is a cliche undertaker, pale skinned, thin, long hat.
P.S. 2 there is a scene where the sister's friend has sex in a hotel room and the boy arrives with glasses and a cane, pretending to be blind and seeing the scene.