If a woman is certain that her husband has died, and after she has observed the ʿiddah of a widow she marries again, in the event that it becomes known that her husband died at a later time and the second marriage contract was in fact concluded while her first husband was still alive or while she was observing the ʿiddah of a widow, then in such a case, she must separate from her second husband and, based on obligatory precaution, she must observe two ʿiddahs.
This means that if she has become pregnant by her second husband, she must observe ʿiddah until childbirth; this ʿiddah is for intercourse that has ensued from a mistake (waṭʾ al‑shubhah). The duration of this ʿiddah is the same as that of the ʿiddah of a divorce. Then, she must observe the ʿiddah of a widow or complete her previous ʿiddah.
If she is not pregnant and her first husband died before she had sexual intercourse with her second husband, she must first observe the ʿiddah of a widow and then observe the ʿiddah of intercourse that has ensued from a mistake. But if she had sexual intercourse before her first husband died, then the ʿiddah of intercourse that has ensued from a mistake must be observed first.