So, Pilate told Aphranius that Judas was going to be killed, which Aphranius said was news to him, and told Aphranius to make sure nothing happened to Judas. Aphranius then goes and kills Judas, comes back to Pilate, and says he's unfortunately failed in his task, makes up an elaborate story about what happened, and volunteers to stand trial for his failure (which Pilate refuses). So far so good, except that we don't know what Aphranius' motive is. Then, Pilate tells Matthew Levi that he had Judas killed.

I get that "Make sure nothing happens to him" might have meant "Take care of him for me, will you Aphranius? (Nudge-nudge wink-wink)", but then what on earth was the point of that elaborate story Aphranius made up and the long conversation he had with Pilate, ostensibly trying to piece together what must have happened? Wouldn't he have just smiled wrily and said something like "Alas, I was too late. I hope the procurator is not too disappointed?", rather than embarking on that long dialogue of deduction in which he contradicted Pilate multiple times? It sounded very like a genuine attempt to make it look as though he was interested in catching the killer, into which he'd put a lot of effort. If that wasn't for the purpose of fooling Pilate, what was it for and who was he trying to fool? Spies? Pilate's own conscience?