An interview with a former spirit worshiper who explains how this is possible and who the spirits actually are. He explains that these spirits pretend to be the spirits of the dead when in fact they are demons (jinn) who are fooling people.
These Jinn work for Satan and work with the people to fool the people of this world. It is these Jinn that the rulers of the world are in contact with and with whom they plot their plots against mankind.
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