They Remembered His Words
Even though they had been able to get Pilate to have Him crucified, they wanted special measures taken that would prevent His resurrection. They asked Pilate to post a guard at His tomb to prevent anything from appearing He had risen from the dead.

  Though they called Him a deceiver, they were afraid of Him. Matthew 27: 3, "...we remember that that deceiver said, while he was yet alive, After three days I will rise again." Isn't is strange how the enemies of Christ as so sure He is not the Son of God but they do everything they can to raise objection to Him? Are they really afraid He is who He claimed to be? Why are they so worried about Him if He is a fake?