A.T. Robertson Commentary Acts 12:19

"And when Herod had sought for him, and found him not, he examined the guards, and commanded that they should be put to death. And he went down from Judaea to Caesarea, and tarried there." — Acts 12:19 (ASV)

He examined (ανακρινας). First aorist active participle of ανακρινω, old verb to sift up and down, to question thoroughly, in a forensic sense (Luke 23:14; Acts 4:9; Acts 12:19; Acts 28:18).

That they should be put to death (απαχθηνα). First aorist passive infinitive (indirect command) of απαγω, old verb to lead away, especially to execution as in Mt 27:31. Here it is used absolutely. This was the ordinary Roman routine and not a proof of special cruelty on the part of Herod Agrippa.

Tarried (διετριβεν). Imperfect active. Herod Agrippa made his home in Jerusalem, but he went to Caesarea to the public games in honour of Emperor Claudius.