Simple, the Romans did. He died a Roman death on orders of the Roman procurator. Read “From Jesus To Christ” by Paula Fredriksen, excellent book (and hands down the best professor I’ve ever had).
Welcome to the Straight Dope Message Boads, SoDamn, glad to have you with us.
It’s very helpful to others if, when you start a new thread, you provide a link to the Staff Report being discussed. In this case, it’s Who killed Jesus?
It may be obvious now, but in a few weeks, folks won’t know what you’re commenting on, and we get duplication and wasted efforts, if you see what I mean. So, providing the link helps keep everyone on the same page.
In response to your comment, that’s certainly one way of looking at it. He not only “died a Roman death on orders of the Roman procurator,” he was tried under Roman law. However, the gospels (the main account of the events) heap mucho blame on the Jews. Certainly the Jewish High Priest bears some responsibility – he was the one who brought Jesus to the Roman justice system, rather than ignore him (for instance). The purpose of the Staff Report was to try to balance what we know today about history, with what the gospels preached or exaggerated.