Here is something like the footstep of one who has worn a shoe; can it be that of our friend?
"I heard a footstep in the hall, and it was my duty to see who was passing," he said.
He had recognised the footstep while it was yet seventy mtres away.
But no footstep ever passed the floor immediately below: except his own.
No sound of footstep was stirring; no sign of human figure ...