Cite the textual evidence from the story where you first figured out the murderer wasn’t human.

From the text:

I tried to put my fingers around the piece of wood, as if it were the girl’s neck! But still my hand was not large enough to equal the marks left by the killer. “Dupin! These marks were made by no human hand!”
“No. They were not. I am almost certain that they were made by the hand of an orangutan, one of those man-like animals that live in the wild forests. The great size, the strength, the wildness of these animals are well known. Now. Look in this book by Cuvier. Read. Look at the picture.”