What is the ruling on praying behind an Imam who writes amulets, talismans, and charms for healing and for bringing love? Is his action considered sorcery? Is it permissible to warn against praying behind him?

A sorcerer is one who practices magic, which affects the mind or body of the bewitched. Sorcery can be a means of drawing closer to Satan, and the magic of affection is a famous example of this. The ruling concerning a sorcerer varies depending on the type of magic he practices. The Shafi'i school of thought holds that a sorcerer is questioned about his magic; if he describes disbelief, he is considered a disbeliever; otherwise, not. Based on this, if his magic does not lead to disbelief, then the ruling on praying behind him is like praying behind a fasiq (transgressor), which is disliked but valid according to the majority of scholars. As for the acceptance of a sorcerer's acts of worship, if his magic renders him a disbeliever, his acts are not accepted. If it does not render him a disbeliever, his sincere acts that conform to Islamic law may be accepted.