The old mans eye was like the eye of a vulture. It drove the killer crazy so he decided to kill the old man to get rid of the eye
Climax
The old man has a eye that looks like it is always watching the killer like a hawk and it drives the killer crazy so he decides to kill the old man by suffocating him
Falling Action
The killer sneaks into the old mans room for the 8th night
Resolution
The guy is suffocating the old man with the weird eye
I feels so confident that no one would find the old mans body that he invited the 2 police that came over because a neighbor heard a scream and put a chair on top of the spot he hid the body
The killer is going crazy because he thinks he is hearing the old mans heart and tells the police that he killed the old man.