What is the Qarīn, and can it be a source of information about a person through magic?

The Qareen (companion jinn) is a devil that accompanies a human. It can be a source of information about that person, as the Qareen informs the sorcerer's Qareen about what it knows concerning the human it accompanies. Some ignorant people then imagine that the sorcerer knows the unseen, but this is a عمل of the deceitful sorcerers who inform strangers about their names and some of their past affairs through inspiration from the devil.