The oldest son of Mattathias of Modein did not take a leadership in the Judean revolt against the Seleucid empire (166 BCE) but aided his younger brothers Judah Maccabee & Jonathan. While on a mission for the latter to ask the Nabateans to store the Jewish rebels' provisions, he & his party were killed in an ambush by residents of Medeba (Jordan), which led the Jews to retaliate.

References: 1 Maccabees 2:2; 9:35-38.
                   Josephus, Antiquities 12.266; 13.8-11.
                    _____, War 1.47.                   

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• John Gaddi - brief entry in Wikipedia's web quotes primary sources.