‘But on the morrow, desiring to know the certainty of what he was accused of by the Jews, he loosed him, and commanded the chief priests and all the council to come together, and brought Paul down and set him before them.'
So on the next day, wanting to know exactly what charges were being laid against Paul, he gave Paul his freedom within the fortress and commanded the Sanhedrin if they wished to justify Paul being handed over to them to gather to discuss the matter and formulate their charges. Then he brought Paul out and set him before the Council.
This chief captain was an object lesson to the Jews. He alone (although he did not know it) was obeying the Law, ‘;-- then you shall enquire, and make search, and ask diligently ---' (Deuteronomy 13:14). That is what the Jews should have done. It took a Roman to hold them to it.
We note that this was at least the sixth time that the Sanhedrin had been called on to evaluate the claims of Christ. The first occasion was when the official Sanhedrin had met to consider reports about Jesus (John 11:47-53); the second was during Jesus' series of ‘trials' (Matthew 27:1-2; Mark 15:1; Luke 22:66-71); the third was for the trial of Peter and John (Acts 4:5-22); the fourth was for the trial of the Twelve (Acts 5:21-40), and the fifth was for Stephen's trial (Acts 6:12 to Acts 7:60). They had had plenty of time to come to a firm and reasonable decision about him. But they had not. They were still divided.