This is not permissible and praying is void there. Asking the dead or believing in their blessing is shirk, let alone slaughtering for them.

many people here in kashmir visit dargahs and mausoleums to pray, but going to dargahs is haraam in islam, so is it allowed to pray there ? And also r these people who go to dargahs out of the fold of islam?

Shirk and its different forms |