Mutarrif narrates: Those people came to a tent, brought a man out of it and killed him. I asked: "What is the matter with him?" The people told me that this man had had relations with his wife's mother, so the Prophet (peace and blessings be upon him) sent people to him, and they killed him.
Ahmad recorded it thus with a munqati' (broken) chain, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الحدود والديات / 10619