What is the book and the source in which Al-Daraqutni mentioned the narration of Saeed ibn Al-Musayyib regarding the killing of Hamza and the death of his killer by drowning in wine?

The aforementioned narration has not been found in the available books of Al-Daraqutni, but some scholars have attributed it to him. Al-Bayhaqi transmitted it in Dala'il al-Nubuwwah with a chain of narrators whose men are trustworthy, and the chain ends with the statement of Hujayn: "I only know that I heard Abdul-Aziz say: And Sa'id used to say: I used to wonder how the killer of Hamza could escape, until it reached me that he died drowned in wine." Al-Bukhari narrated it in his Sahih without the latter statement of Hujayn.

Islam obliterates what preceded it, and a Muslim is not held accountable for what he did during the جاهلية (pre-Islamic era) regarding the rights of Allah or people. The evidence for this is the Almighty's saying: "Say to those who have disbelieved, if they cease, what has passed will be forgiven for them," and the Prophet's (peace be upon him) saying: "Islam obliterates what came before it." Many who killed men during the جاهلية embraced Islam, and the Prophet (peace be upon him) did not hold them accountable for that.