Assalaamu 'alaikum
How do you know if someone has been afflicted by black magic? What can you do to ward off such evil?
JazakAllahu khairan.
Wassalaamu 'alaikum
99.9% of the times, it is merely awhaam (delusions, imaginations and assumptions) in our minds that somebody has performed black magic. Much evilness is needed to perform such an act. A person jeopardises his Imaan by performing it. I can't imagine many people who would perform such an act that would jeopardise their Imaan.
Many of the people of the indo-pak subcontinent are under the misconception of this. As soon as somebody in their family falls ill, they believe that they have become possessed or something of this sort.
Such thoughts should be avoided. After all, illness is from Allah Ta'ala and can befall any of his creation.