Praying behind someone who writes Taweez

Praise be to Allaah.

Firstly: it is permissible to pray behind one who writes amulets from the Qur’aan and prescribed du’aa’s, but he should not write them, because it is not permissible to hang them on one’s body or elsewhere. But if the amulets include anything that constitutes shirk, then you should not pray behind the one who writes them. It should be explained to him that this is shirk and the one who should do that (explain this) is one who has knowledge of this matter...

And Allaah is the source of strength. May Allaah bless our Prophet Muhammad and his family and companions, and grant them peace.

Fataawa al-Lajnah al-Daa'imah, 3/65

Source (Summarised): Islam-qa, question 12000: Is it permissible to pray behind an imaam who makes amulets for people, then if a drought comes he tells the people to buy a ram or a cow, and to slaughter it and let the young boys eat it at the time of the drought, so that rain will come? Is it permissible to pray behind an imaam who makes vows and offers sacrifices to something or someone other than Allaah?