I would also recommend Paula Fredriksen’s Jesus of Nazareth, King of the Jews: A Jewish Life and the Emergence of Christianity. She argues in favor of John’s account of multiple trips to Jerusalem throughout Jesus’s public life as a reason why Pilate may have acted the way he did – he knew Jesus wasn’t really a threat, but he needed to make an example of him. This would explain why the Romans didn’t go after his followers. The book has a fairly useful bibliography as well.
Her other book, From Jesus to Christ: The Origins of the New Testament Images of Jesus, is pretty good, too.