Perhaps but just because there's scratches doesn't automatically equal demons. What else has been happening? If all you claim is scratches, and other people are saying things, I don't think it's a demon, it could be a spirit, but probably people are scaring you into believing something that isn't there. [Demons attacking people are very rare]
You can simply cleanse and protect yourself, your friends, and your home and the being should leave you alone. Once you've cleansed and protected, adopt the belief 'ignorance is bliss' because if you doubt you cast properly, or conclude everything is the result of a negative being, you are welcoming negative energy into your life and leaving a doorway open for the being to return.