Pilate is a fascinating historical figure. For a man who so (in)famous, we know remarkably little about his life. The tradition of the early Church is not unanimous in its treatment of him. To most western Christians he is a rather villainous figure. But at least some of the non-Chalcedonians venerate him as a saint.
Philo gives a rather negative picture of him.
John 18:28 makes it explicitly clear that the Jews would not enter Pilate's palace for reasons of ritual purity. Yet, in John 18:33 Pilate reenters the palace and has Jesus summoned inside where Pilate interrogates Christ in private, away from the mob...and yet the specific details of that interrogation were at some point related to the writer of John.
Clearly, someone privy to that exchange associated himself with the early Christian community closely enough to relate the entire account. It would seem to me the audience would have been quite limited, restricted to Pilate, a handful of his confidants or advisors and a few Roman guards...at least one of whom apparently became an early convert.
Pilate was just the vessel thru which God worked.
Pilate had no choice, but to go along with the force of the Holy Spirit.
He knew Jesus was innocent and even gave the Pharisees a choice to save Barrabas or Jesus. They chose Barrabas...............