Answer: It is not permissible to offer Salah behind any Mushriks (one who associates others with Allah in His Divinity or worship) including those who seek the help of others beside Allah. Seeking help from the dead, idols, Jinn, and the like is an act of Shirk (associating others with Allah in His Divinity or worship). However, asking for the help of living beings who can give it is permissible. Narrating the story of Musa (Moses peace be upon him), Allah (Glorified and Exalted be He) states: The man of his (own) party asked him for help against his foe If you do not find an Imam to offer Salah behind , it is permissible for you to offer it home. If you find a group of Muslims who can offer Salah in the Masjid (mosque) before or after this Mushrik Imam offers it, you should offer Salah with them. If Muslims are able to fire this Imam and appoint another Muslim Imam, they should do so. This is a form of enjoining the right and forbidding the wrong to enforce Allah's Shari`ah (Law) in the land. If this is possible without creating any dispute. Allah (Exalted be He) states: The believers, men and women, are Auliyâ' (helpers, supporters, friends, protectors) of one another; they enjoin (on the people) Al­Ma'rûf (i.e. Islâmic Monotheism and all that Islâm orders one to do), and forbid (people) from Al­Munkar (i.e. polytheism and disbelief of all kinds, and all that Islâm has forbidden) Allah (Glorified and Exalted be He) also says: So keep your duty to Allâh and fear Him as much as you can The Prophet (peace be upon him) stated: "Whoever, among you, sees something abominable should rectify it with his hand. If he does not have sufficient strength, then he should change it with his tongue. If he does not have sufficient strength to do it, (even) then he should abhor it in his heart and that is the least of Faith." Related by Muslim in his Sahih.