“The first crime of the new reign was the murder of Postumus Agrippa. Though he was surprised and unarmed, a centurion of the firmest resolution despatched [sic] him with difficulty. Tiberius gave no explanation of the matter to the Senate; he pretended that there were directions from his father ordering the tribune in charge of the prisoner not to delay the slaughter of Agrippa, whenever he should himself have breathed his last…It was more probable that Tiberius and Livia, the one from fear, the other from a stepmother’s enmity, hurried on the destruction of a youth whom they suspected and hated” (Tactius, Annals, Book 1)

Tacitus is trying so hard to blame Livia for everything, however, it seems far more reasonable to believe Tiberius murdered Postumus to test his new power. His mother, Livia, even if she was ‘evil’ wouldn’t have any reason to kill Postumus. Tiberius was already in power and Livia wouldn’t want to upset…