[Ruling on Praying over One Accused of Drinking Poison]

Answer—and Allah is the One who grants success: What is obligatory is to remain upon loyal solidarity (walāʾ)—and that entails the permissibility, recommendation, and desirability of supplicating and seeking forgiveness for her. It is impermissible to depart from this except by clear, decisive proof. The Exalted says: “O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin.” [al-Ḥujurāt:12] And He, Exalted is He, says: “O you who have believed, fear Allah and speak words of appropriate justice.” [al-Aḥzāb:70] And He, Exalted is He, says: “And do not pursue that of which you have no knowledge. Indeed, the hearing, the sight and the heart—about all those [one] will be questioned.” [al-Isrāʾ:36]
The spread of the claim among people that she drank poison is not a clear proof, for falsehood often circulates among them—as Allah related in the story of the slander: “When you received it on your tongues and you said with your mouths that of which you had no knowledge …” [al-Nūr:15]. Her request for forgiveness is not proof either.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1