for all those who do not beleive that black magic exist read the Quran , two angel were sent down teaching black magic to test people there names are Harut and Marut as it says in the Quran. they were sent down to see which people would go on to use black magic against people and when this was established they were removed.
allah forgive me for any mistakes i have made in the above content but i read this is Surah Baqrah
Read post # 93 for understanding what is said in Quran about magic.