The third removal was that of Agrippa Postumus. He had been alongside his elder brothers at the celebrations marking the dedication of the Temple of Mars in 2 BC. In AD 4, Agrippa had been adopted by Augustus. His elevation followed the deaths of his brothers, Gaius and Lucius, and would seem to have been the logical continuation of Augustus’ elevation of his grandchildren.
But Agrippa’s path to power was not smooth. When the Pannonian war broke out in AD 6, Germanicus, not Agrippa, was sent to support Tiberius. Germanicus was just a little older, but the passing-over of Agrippa seems notable. Character weaknesses are cited. But this seems a prelude to his exile, presumably soon after, in part for open opposition to Livia and complaints about his own mistreatment (Dio, 55.32).
Tiberius had previously shown himself intolerant of potential rivals for the imperial succession and lost out to Gaius and Lucius. In the circumstances of his return, he was in a more powerful position and with Livia also at the heart of the regime, Postumus’ chances of gaining acceptance were slight. His removal cleared the imperial family of possible rivals to Tiberius. In retrospect his murder in AD 14 when Tiberius came to the throne, can be seen as both a reflection of the increasingly brutal dynastic politics of the last decades of the Augustan regime and a harbinger of the brutal factional violence of the Tiberian period.
Of Agrippa and Julia’s children, only Agrippina remained in Rome. She was married to Germanicus and presumably protected by that relationship. Germanicus himself. But with most of her family exiled, her position was likely felt to be precarious and the roots of the conflict between her and Tiberius which were to be so damaging later in the reign were already in place.