You can all the newspaper accounts of their bloody crimes here. The family killing spree included an innocent widow. They even crudely beheaded one of their victims and threw his head in a nearby river. The father and oldest brother were charged, but found only guilty of being accomplices, as they were "not present" at the time of the gruesome murders. They were not executed.
Their father was the only member of their family to attend their hangings and he left before the execution began. 7,000 people attended the hangings. It took George only nine minutes to die from his neck being broken. Andrew died after eleven minutes from strangulation. Andrew left behind a wife and two sons. George left behind a wife and one son.
You can read more about the vigilante gang and their crimes and the trial here:
List of Executions by Name In Texas