What do we know about the old man in the story "The Tell-Tale Heart"?

Although the main charactor of the classic Edgar Allan Poe
short story, "The Tell-Tale Heart," is a madman and, thus, an unreliable narrator, we
are told that he "loved the old man." The old man was apparently wealthy, for the
narrator states that he had "no desire... for his gold." The old man must have trusted
the narrator, since he allowed him to live in his home. The old man is described as
having an evil eye--"the eye of a vulture... all a dull blue, with a hideous veil over
it"--and it was his eye that caused the narrator to kill the old
man.

The old man always went to bed long before midnight,
since it was at that time that the narrator sneaked into his room each night. For a week
the narrator looked into the old man's room, but he refused to kill him since the
vulture eye was always closed. The old man suspected nothing, since the narrator treated
him kindly each day. On the eighth night, the old man heard a noise, and he sat up in
bed. When the old man groaned, the narrator knew it was one "of mortal terror." When the
murderer finally made his move, the old man "shrieked once--once only." His body was
then dismembered and "deposited" beneath the planks of the
floor.