Two Texas brothers, Alejandro Treviño, 18, and Christian Treviño, 17, along with their friend, Juan Eduardo Melendez, 18, are all in jail after being arrested in the beating death of the boys’ stepfather, 42-year-old Gabriel Quintanilla. The boys allegedly beat Quintanilla to death when they discovered that the grown man had been molesting their 9-year-old sister.

According to authorities, the incident began at an RV park, where the boys’ sister made an “outcry” about being “inappropriately touched” by Quintanilla (who is her biological father). When the teenage boys discovered the girl’s accusations, they became “enraged” and “confronted” their stepfather. The three of them got into a “physical fight” before Quintanilla fled on foot to a nearby apartment complex.

Brothers Alejandro and Christian Treviño contacted their friend, Juan Eduardo Melendez, who drove them to the complex where they, once again, confronted and assaulted Quintanilla. The three young men briefly left Quintanilla in order to change vehicles. The next time they came upon Quintanilla, he was “walking alone and injured,” according to Pharr police. It was then that the third and final assault happened.

The police say that the young men beat Quintanilla with brass knuckles. He died due to blunt force trauma of the head. The young men dumped his body in a nearby field, where it was later discovered by a farmer.

The young men are being charged with capital murder, aggravated assault, and engaging in criminal activity, save for Alexandro Treviño, who is not being charged with capital murder, as he didn’t deal a fatal blow. Melendez is also being charged with “possession of marijuana.”

According to police, at the time of his death, Gabriel Quintanilla already had a warrant out for his arrest for “continuous sexual assault of a child” and for “assault, family violence.”

With a man dead, three young men in jail, and a young girl no doubt traumatized, people can’t help but be frustrated over how the system failed this entire family.

Online, users are discussing questions about how much mercy we should offer to adults who resort to violence to protect the children in their lives. Questions like: Is it okay to use violence against someone who is committing a despicable act on a child? Would you do the same thing in their position? Were the boys justified in their actions?

“Well there are laws,” wrote one Twitter user. “They still committed a crime even though they had good intentions and reasons.”

“They did what needed to be done,” wrote another. “The abuser had a warrant for continued sexual abuse and no one did anything to stop it. These boys did nothing wrong, they just protected their sister. What I’m wondering is, where was mom?”

According to Quintanilla’s niece, Zee Gomez, the 9-year-old girl’s mother (who is also mother to Alejandro and Christian Treviño) was aware of the abuse going on.

“CPS (Child Protective Services) opened a case with their family a while back, since they had lived with Gabriel for a while,” Gomez wrote on Facebook. “So after all this, she still let him in her house, let him stay the night and all.”

Gomez also added that neither Alejandro or Christian were “aware of the warrant or what [Quintanilla] had done.” “CPS doesn’t tell the kids about this but they sure talked to the mom about it.”

If you or anyone you know has experienced sexual assault, please call 800.656.HOPE (4673) or visit https://www.rainn.org. If you think a child is in danger, call Childhelp at 800.4.A.CHILD (800.422.4453)