I heard all things in the heaven and in the earth. I heard many things in hell.
Mentally insane Claim#2 Killer is insane
I loved the old man. He had never wronged me. He had never insulted me, nor did I want his gold. He had the eye of a vulture!
Mentally insane Claim#3 Killer is insane
The narrator claims that he could hear heaven and earth, which is impossible. People cannot hear the sounds of heaven but because he claims he can hear heaven and earth means that he is most likely hearing voices or in his mind, making him insane as he could not tell what he was doing.
The narrator had no hatred towards the man, and had no greed towards him. The narrator is mentally insane because he decides to kill a poor, innocent man just to not be able to see his eye. Normally if people do not wish to be looking at things and if it disturbs them, they would leave instead of deciding to kill them.