[Full question: If a married woman is raped by her real father-in-law, will her wifehood [sic] be changed, i.e., will she no longer remain the wife of her husband or will she be considered as divorced and will she become haram (forbidden) for her husband? If it is so, will she be married anew to her rapist father-in-law? And whose children will those five existing children be considered? Will these children be considered brothers and sisters of their father?]
Answer: If someone has committed adultery with the wife of his son, and if this has been proved by the depositions of witnesses or if his son confirms it or if the woman herself admits and confirms it, the wife of the son becomes haram forever for the son. If the father copulates with a woman either legally after marriage, or illegally without marriage, in both cases it becomes haram for a man [son] to keep her her in his marriage.
If is mentioned in the Quran: "wa la tankihoo ma nakaha aaba-o-kum" [And marry not women whom your fathers married -- Quran, 4:22], i.e., the son should separate himself from his wife and never go to her. The contention of the panchayat people that the wife of the son has now become wife of the father and her wifehood [sic] has changed is not correct, or to say that the wife of the son is divorced is also not correct. Neither she can be married to her father-in-law. All the five children are legitimate children of their real parents. They will be considered grandsons and granddaughters of their father's father and not brothers and sisters of their father.
[Note: Imrana was a 28 year old Muslim woman living Muzaffarnagar India. She was raped by her father-in-law on June 6th 2005 after which Deoband issued a controversial fatwa which ordained that Imrana and her husband be separated and their marriage to be nullified. They were interpreting the Quranic verse, "And marry not what your fathers have married" (4:22). Many women activist groups and as well as Muslim organizations condemned the fatwa.]