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 Hérode, s'étant mis à sa recherche et ne l'ayant pas trouvé, interrogea les gardes, et donna l'ordre de les mener au supplice. Ensuite il descendit de la Judée à Césarée, pour y séjourner.