Who told Luke what Stephen told to the Sanhedrin?

All right, I started to think who told Luke what Stephen told to the Sanhedrin.  I could be wrong but I kind of think that just not anybody could have gone into the Sanhedrin while they were in session.  They had their guards, they told people to leave and to come in.  Keep this trial in house.  I rather figure that none of the disciples or apostles where there and they would not be allowed to attend.  Their lives might have gone the way of Stephen.  Anyway, where were the Apostles when Stephen was taken and in trial for his life?  Now, we know there was a man, named Saul that was there and he had to hear every word that Stephen said.  We know that Saul gave his approval to Stephen death.  We know the personality of Paul from his writings that when he did something, he did it with all his might.  Saul then began to destroy the church.  He had to have some power to be able to this.  Saul hated the disciples and then receives letters from the high priest to take them to Jerusalem to have them killed.  We know that Luke traveled with Paul and Paul really never forgave himself for what he did to the Body of Christ and to many individuals.  Paul through the Holy Spirit had to be the one to give Luke the information on what Stephen said, done and how he died.  I believe we have some inside information on this event in church history from Paul through Luke.  Just a thought.

Blessing.

Stephen

(Acts 8:1 NIV)  And Saul was there, giving approval to his death. On that day a great persecution broke out against the church at Jerusalem, and all except the apostles were scattered throughout Judea and Samaria.

(Acts 8:3 NIV)  But Saul began to destroy the church. Going from house to house, he dragged off men and women and put them in prison.

(Acts 9:1-2 NIV)  Meanwhile, Saul was still breathing out murderous threats against the Lord's disciples. He went to the high priest {2} and asked him for letters to the synagogues in Damascus, so that if he found any there who belonged to the Way, whether men or women, he might take them as prisoners to Jerusalem.