Strange stairwell sounds

     Things seem to be picking up. Tonight as I sat at the computer I heard, very distinctly, the sound of someone or something heavy ascending the rear staircase. My wife was not home yet and my dog is neither heavy nor tall enough to reach the handrailing. Many years ago, when this house was a rest home, the owners installed handrails on both sides of the rear stairs to the second floor. These handrails were not installed very well; if anyone has problems climbing stairs and has to use the handrails for support they creak and groan in a very characteristic manner. This is what I heard as I sat at the computer , in the library, tonight. My dog heard the sound as well and went into a barking fit. His reaction gave me cause to check out this intruder. The doors were locked and no one was to be seen anywhere. My dog settled down as soon as we returned to the library. I never have the recorder recording in the right places.