A.T. Robertson Commentary Mark 14:64

"Ye have heard the blasphemy: what think ye? And they all condemned him to be worthy of death." — Mark 14:64 (ASV)

They all (ο δε παντες). This would mean that Joseph of Arimathea was not present since he did not consent to the death of Jesus (Luke 23:51). Nicodemus was apparently absent also, probably not invited because of previous sympathy with Jesus (John 7:50). But all who were present voted for the death of Jesus.