Robert Gene Garza says he was 9 or 10 when he joined a far South Texas street gang called the Tri-City Bombers.
By age 20, he was on death row, convicted of participating in a 2002 gang ambush in Donna in the Rio Grande Valley where four women were shot dead.
He's also been linked to another shooting where six people were killed in Edinburg.
The now 30-year-old Garza is facing execution Thursday evening in Huntsville.
His lethal injection would be the 12th this year in Texas and likely the last to use the state's existing supply of pentobarbital as the execution drug.
Texas prison officials have said their inventory is expiring and they'll need to find another source or another execution drug.
Another punishment is scheduled for next week.