eye witness of what?
Babylonian Talmud “It has been taught: On the eve of Passover they hanged Yeshu. And an announcer went out, in front of him, for 40 days (saying): ‘He is going to be stoned, because he practiced sorcery and enticed and led Israel astray. Anyone who knows anything in his favor, let him come and plead in his behalf.’ But, not having found anything in his favor, they hanged him on the eve of Passover.” Sanhedrin 43a; df.t.Sanh. 10:11; y. Sanh. 7:12; Tg. Esther 7:9 (Another version of this text reads: “Yeshu the Nazarene.” Yeshu or Yehoshua is Hebrew (or Aramaic) for Jesus’in English this name is also translated “Joshua.” The Old Testament hero bore the same name as Jesus the Messiah. “Hanged” is another way of referring to a crucifixion; see Luke 23:39 and Galatians 3:13
So was he hanged, or stoned? What is the testimony? Where is Pilate? This account differs from the gospel, and can not be used as corroboration with the bible account.
Just a guess, but it may have had something to do with the Pharisees trying to come up with the initial judgment against Jesus (which, like Stephen, would have been stoning). The Pharisees had been trying to trap Jesus with His words for a long time. But then the Pharisees became afraid of the people following Jesus, so they trumped up the political charges to hand Him off to the Romans.
Where of course he was traded for Barabas and ended up hanging on the cross.
It has been taught:
You appear to 'have been taught' something different.