Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[320] So the king produced those that had been tortured before the multitude at Jericho, in order to have them accuse the young men, which accusers many of the people stoned to death; and when they were going to kill Alexander and Aristobulus likewise, the king would not permit them to do so, but restrained the multitude, by the means of Ptolemy and Pheroras. However, the young men were put under a guard, and kept in custody, that nobody might come at them; and all that they did or said was watched, and the reproach and fear they were in was little or nothing different from those of condemned criminals: and one of them, who was Aristobulus, was so deeply affected, that he brought Salome, who was his aunt, and his mother-in-law, to lament with him for his calamities, and to hate him who had suffered things to come to that pass; when he said to her, "Art thou not in danger of destruction also, while the report goes that thou hadst disclosed beforehand all our affairs to Syllcus, when thou wast in hopes of being married to him?" But she immediately carried these words to her brother. Upon this he was out of patience, and gave command to bind him; and enjoined them both, now they were kept separate one from the other, to write down the ill things they had done against their father, and bring the writings to him, So when this was enjoined them, they wrote this, that they had laid no treacherous designs, nor made any preparations against their father, but that they had intended to fly away; and that by the distress they were in, their lives being now uncertain and tedious to them.