Jeremiah 41:1-3

Now in the seventh month Ishmael the son of Nethaniah, the son of Elishama, of the royal family [of David] and one of the princes of the king, came [at the instigation of the Ammonites] with ten men to Gedaliah the son of Ahikam in Mizpah. As they were eating a meal together there in Mizpah, Ishmael the son of Nethaniah and the ten men who were with him got up and struck down Gedaliah the son of Ahikam, the son of Shaphan, with the sword and killed the one whom the king of Babylon had appointed [governor] over the land. [2 Kin 25:25] Ishmael also killed all the Jews who were [at the banquet] with Gedaliah at Mizpah, in addition to the Chaldean soldiers who were there.