That was not the case...
That was not the case, so how could the Prophet of Allah (P) kill and mutilate them in this way without investigation and cross examination until it became clear who among them was the murderer so that he could kill him for that?
Perhaps some would say that they all participated in killing him, could the Prophet of Allah (S.A.W.) not forgive and pardon them for they were Muslims as proved by their words "O Prophet of Allah?" Did the Prophet of Allah not hear Allah's words: "And if you punish them, then punish them the way you were punished. And if you are patient then that is better for those who are patient" (16:126).
This verse was revealed to the Prophet of Allah (S.A.W.) when his heart was burning over his uncle, the master of the martyrs, Hamza b. 'Abd al-Muttalib whose stomach they had slashed open, and eaten his liver and cut his private parts. The Prophet was enraged when he saw his uncle in that condition. He declared: "Should Allah let me prevail over them, I will mutilate seventy [of them]".
Whereupon the verse was revealed unto him and he said: "I shall be patient, O my Lord.” He then forgave Wahshi, the murderer of his uncle as well as Hind who had mutilated his pure body and ate his liver. This was the [true] character of the Prophet (P). What proves the repulsive [nature] of the narration and that the narrator himself found it abominable, is that he followed it up by saying: "Qatada said: 'Muhammad b.
Sirin informed me that this occurred before legal punishments were revealed ...'" to justify, by that, the actions of the Prophet (P). Far removed is the Prophet from judging by himself before his Lord made matters clear to him. If he did not judge in even trivial matters until revelation came to him, what do you think about matters pertaining to blood and penalties?
It is very easy for anyone who reflects upon the matter to realize that it is a narration forged by the Umayyads and their followers to please the rulers who did not hesitate to kill innocent people based on suspicion and accusation, mutilating them in a hideous manner.