The guards are killed because they allowed a prisoner to escape and because Herod is furious that Peter has not been found.1 If Peter’s trial was meant to take place early in the morning, then it would have been public knowledge that he escaped from Herod.
19 And after Herod searched for him and did not find him, he examined the sentries and ordered that they should be put to death. Then he went down from Judea to Caesarea and spent time there.