What is the ruling on burying a Muslim woman—who concealed her Islam for fear of her extremist family—in Christian cemeteries?

The Muslims in that country were obliged to cooperate in washing, shrouding, praying over, and burying this Muslim woman in the Muslim cemeteries, if she had truly embraced Islam. If they were unable to do so, there is no sin upon them.

If her burial was recent and it is possible to exhume her from her grave before her body changes, so that she can be buried in a Muslim cemetery, washed, shrouded, and prayed over, without any preponderant harm, then this must be done.

If that is not possible, then it is permissible to pray over her grave, and the obligation of washing and shrouding is waived due to the excuse.

If her grave is unknown, then one should pray towards the direction of the cemetery, facing the Qiblah, with the intention of praying over her. This is sufficient if the specific grave is not known.

The man must be aware of the danger of friendship between women and men, and he must fear Allah and repent to Him for befriending foreign women, and know that this door is one of the greatest doors to evil and means of corruption.