Matthew 26:59

‘Now the chief priests and the whole council sought false witness against Jesus, that they might put him to death,'

Then the Chief Priests and the whole of the council who were present (only twenty three were required to make it official) sought to amass a case by which they could have Jesus sentenced to death. It is actually irrelevant as to whether the Sanhedrin had the power to put men to death, (it is possible that they could do so for blasphemy), for their aim was not to put Jesus to death themselves, even if they had had the power to do so, which is doubtful (John 18:31). They knew that that would totally discredit them in the eyes of the people. Their aim was rather to get Pilate to do it, but their problem then was that they had to find a charge which would carry weight with Pilate. The suggestion that they sought ‘false witness' does not signify that they were trying to persuade people to invent charges, it simply means that they were looking for anyone who could say something against Jesus which might be helpful to their case. Such people had to be ‘false witnesses' in the eyes of the writer for anything they said that was derogatory against Jesus would clearly not be fully true, but it does not mean that they were recognised as being such by those who called them. What the judges were looking for was true witnesses who could really demonstrate a case against Jesus, even though all they got in the end was false witnesses, none of whom agreed with each other on anything essential. So this does not brand the Chief Priests as necessarily exceptionally dishonest, it simply indicates that in their desperation to obtain a conviction they were willing to take advantage of anything that they could get their hands on. It should be noted that this band of witnesses must either already have been sought out in readiness for any trial that there might be, and thus have been all ready to be called on at a moment's notice, or alternatively must have been hastily gathered as a result of enquiries among their own bands of servants and slaves, many of whom would no doubt previously have shown a discreet interest in what Jesus had to say.