It is narrated from Amr bin Umayyah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) sent him alone to Quraysh to gather intelligence. He said: I came to the wooden post on which Khubayb was crucified, while I feared the enemy's spies. I climbed it and untied Khubayb, and he fell to the ground. I moved a little distance away, then I looked and it seemed as if the earth had swallowed Khubayb, and to this day Khubayb has not been seen anywhere. Abu Bakr bin Abi Shaybah said: Ja'far bin Awn narrated this from Ja'far bin Amr bin Umayyah, from his father, from his grandfather.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4178