My understanding has been that Jesus was killed at the hands of sinners, however I also have learned that He was betrayed by His own people, His own tribe, being Judah, and even His betrayer is named for that tribe, Judah. He was sentenced by Pontius Pilate at the insistence of Jews who, when Pilate asked if they would have their King released, cried all the more, crucify Him, we have no king but Caesar. My bottom line belief on this is that Jesus, Yeshua, was killed by mankind at the demand of some Jews and at the hands of Romans. I do know that all who sin have a hand in our Beloved Savior's suffering and death, yet He forgives us all, and we should be as much as He as is possible.