Magick can prove to be an insidious excuse for violence, as it instills fear and its use is difficult to demonstrate reliably. Just like the witchcraft persecutions in Europe centuries ago, it appears from the article that the victims were not witches or wizards or spiritual workers of any sort, just elderly folks who had managed to accumulate enemies over the years.
The times and places may change, but human nature and mob psychology stay pretty much the same.
UPDATE: Today arrests have been made in the case, just one day after the killings. Hopefully this will help keep the violence from continuing or escalating.