The man was always saying how he had slept.That happened for next 7 nights,he will always ask him how he had slept.
Check well,and his belongings are untouched.
The man finally attacked the old man while the old man was scared and thought by the time he heard the noise his heart will explode.
The man dragged the old man and put the mattress over the man until his heart stopped beating then buried him beside the old mans bed.
The neighbor heard a scream and alerted him,and he called the police to go with him to check it out,and they searched the whole house then they checked his chainber,and they found nothing.
The man finally confesses were he hid the body and he could hear the heart beating but not them.They thought he was crazy.Until they found out the man killed the old man and saw where he hid the body.