Is the testimony of a hidden witness (Mustakhfi) admissible?
General Chapter
Al-Mughni
Book of Testimonies
Primary text
The testimony of a hidden witness is permissible, provided the witness is reliable (Adil). A hidden witness is one who conceals their presence from the person being testified against to overhear their admission without the knowledge of the declarant, such as when someone denies a right publicly but admits it privately. The correct narration affirms the admissibility of such testimony. This view is supported by 'Amr ibn Hurayth, who stated that this method should be used against the deceitful and the wicked, and it is related that Shurayh also held this view. This is also the position of Al-Shafi'i.
Supporting text
An alternative narration attributed to Ahmad, favored by Abu Bakr and Ibn Abi Musa, rejects the admissibility of such testimony. This rejection is also attributed to Shurayh and Al-Sha'bi, citing the Quranic prohibition against spying, {and do not spy} (Quran 49:12). Evidence cited against it includes a narration that whoever relays a hadith and then looks around cautiously (Iftat), the hadith becomes an amanah (trust) for the listener, implying one should not disclose what was said under such guarded conditions. Malik's view is conditional: if the person being testified against is weak and easily deceived, the testimony is rejected; otherwise, it is accepted.