Mark 14:55

Now the chief priests and the whole council sought witness against Jesus to put him to death; and found it not.

What happened to their traitor-witness, Judas? During the night, Judas had heard of developments, and the next morning, after Jesus was bound over to the governor, he flung the money at the feet of the high priest, confessed his sin of betraying innocent blood; and, from the total lack of any testimony from Judas at the trials, it may be assumed that he refused to aid the campaign against Christ any further. He died the same day, a suicide.

The whole council ... has been interpreted as suggesting the scene of the daybreak meeting; but the long and extensive search for witnesses indicates the all-night preliminary trial in the palace of the high priests. We may explain it by assuming that most of the council were present at both trials.