Romans, of course--contrary to anything Matthew or John might have said. They were an occupying army with a keen interest in suppressing possible messiahs who might lead revolts. And they no doubt liked it very much when a vichy goverment like the Sanhedren deflected they ire of the populace away from the Romans. Jewish tradition does not support the Cross, it supports stoning. The cross was a roman invention of jurisprudence.
I'm confident we can disregard Matthew, John, Luke and Mark and conclude that Jesus died in a car accident.
Matthew says that Jesus was condemned by the jews present, and that they jews proclaimed that "His blood be upon us, and our children.". Matthew has the jews condemning themselves for the death of christ. Are you incapable of reading the Gospels you appear to want to defend?