The book of Acts says that James of Zebedee was killed by Herod Agrippa, but does not say why. There is nothing about a trial or a Roman soldier. The story I am referencing come from Eusebius, who cites a lost work of Clement of Alexandria:

2. And concerning this James, Clement, in the seventh book of his Hypotyposes, relates a story which is worthy of mention; telling it as he received it from those who had lived before him. He says that the one who led James to the judgment-seat, when he saw him bearing his testimony, was moved, and confessed that he was himself also a Christian.

3. They were both therefore, he says, led away together; and on the way he begged James to forgive him. And he, after considering a little, said, “Peace be with you,” and kissed him. And thus they were both beheaded at the same time. (** you do not have permission to see this link **)