Much of Edgar Allen Poe's writing deals with murderous, dark people.
Be careful with this. The statement is not true. The basis of Poe's work is that the people in the stories are ordinary people who have dark impulses, and some circumstance drives them into their darker selves.
That being said, your analysis is pretty standard. I'm not sure what you're supposed to do exactly, but I'd take the time issue and really develop it. I'm talking a couple of pages worth. It's that important to the story.
So are the visual and auditory cues. That's another area that can really be developed.
There are a lot of ways you can go with this. I think, unless you've just been asked to give a summary, it would be great if you could take an idea and just go with it. It's more fun, too.