Gospel of James
The Gospel of James, a 2nd-century apocryphal work, recounts that, at the time of the massacre of the Innocents, when King Herod ordered the slaughter of all males under the age of two in an attempt to prevent the prophesied Messiah from coming to Israel, Zechariah refused to divulge the whereabouts of his son (who was in hiding), and he was therefore murdered by Herod's soldiers. This account is also present in subsequent Eastern Orthodox tradition.