Two brothers in Texas were arrested for allegedly beating their stepfather to death after he was accused of sexually abusing their half-sister, San Antonio Express-News reports

Authorities suspect Alejandro Trevino, 18, and Christian Trevino, 17, got into a physical altercation with their 42-year-old stepfather Gabriel Quintanilla at a trailer park before they all dispersed. Juan Eduardo Melendez, a friend of the Trevino brothers, drove Alejandro to a nearby apartment complex as Christian pursued Quintanilla on foot, and assaulted him again. 

The Trevino brothers, along with Melendez, fled the scene to switch from a red Dodge Charger to a pickup truck, and return to the complex in pursuit of Quintanilla. When he was found walking alone, Quintanilla was “beaten to death” with brass knuckles, police said. He was then thrown into the bed of their truck and transported to a city several miles away where his body was dumped in an open field. 

His body was found last week, and an investigation was launched into his death. It was determined that he was killed by severe blunt force trauma to the head. 

Christian and Melendez have been charged with capital murder, aggravated assault, and engaging in organized criminal activity. Alejandro was given aggravated assault and engaging in organized criminal activity charges. All three are being held on a bond of at least $1 million. 

According to FOX5 Atlanta, the Trevino brothers first attacked Quintanilla after discovering from their 9-year-old sister that she was being sexually abused by her father. A Change.org petition was started in support of the release of Melendez, and Christian and Alejandro Trevino. As of this writing, the campaign has received over 21,000 signatures.