Mostly because He refused to accept the teachings of the oral law.
The Pharisees which were Jewish religious leaders
to wait
The Jews are blamed for the death of Jesus because it was the Jewish religious leaders who manipulated Herod and Pilate into crucifying Jesus by charging Jesus with breaking certain Jewish laws making him worthy of death. The Romans would have rather released Jesus that day and crucified Barabbas. But the Jewish mobs at the behest of the Jewish leaders clamored for the release of Barabbas and the crucifixion of Jesus.
heresy
Sabbath.
Jesus knew the Jewish scriptures well but seemed to contradict what they thought was the Law. Jesus challenged their interpretation of the Law.
Caiaphas was High Priest. Jesus was sentenced to death on the orders of Pilate, the Roman Governor because the Jewish leaders had no authority to do so. The Pharisees and priests, as a committee, urged Pilate to condemn Jesus.
The Jewish leaders did not like Jesus. He taught and preached the true word of God. Many of the people were beginning to believe in Him and turning away from the Jewish leaders teachings. So they crucified Jesus and thought they had got rid of the problem. They could now go on teaching in their perverted ways. But what happens? Here the apostles of Jesus start teaching the ways of Jesus and even healed a few persons. This upset the Jewish leaders. They thought they had got rid of the problem and now it was manifesting itself again. The leaders told the apostles to stop teaching in Jesus' name. This is all they could do because the true cause, "the way" was so popular killing the apostles would be a big mistake. The apostles did not stop preaching, and this is a good lesson to whether we should obey man or God, when it come to the important things of God.
Only a roman ruler could legally order an execution, which is what the Jewish leaders wanted.
He was influential enough to rattle the Jewish leaders enough that they wanted to get rid off him.
The Roman authorities saw Jesus as a potential threat to their power and authority, especially after he was hailed as the King of the Jews. They also yielded to pressure from Jewish religious leaders who viewed Jesus as a blasphemer. Jesus' teachings and growing popularity created unrest among the people that the authorities wanted to quell.
The Romans wanted the bodies on the crosses to be taken down before the Jewish sabbath.