A Border Patrol agent has for the first time been indicted on a murder charge after shooting and killing a Mexican national through the border fence, reports the Los Angeles Times .

The border Arizona shares with Sonora, Mexico, is a hot spot for getting “rocked,” which is Border Patrol shorthand for pieces of concrete that are thrown at agents over the fence. The Border Patrol’s policy is to treat such rock-throwing as a threat to agents’ lives, and they are permitted to respond with lethal force.

On Oct. 10, 2012, Agent Lonnie Swartz fired at least 10 rounds through the border fence into Nogales, officials said. At least eight rounds struck Jose Antonio Elena Rodriguez, 16, who bled to death.

It is common for agents to shoot through the border fence, and they usually avoid discipline in such cases.

But on Wednesday night, a grand jury handed up an indictment of second-degree murder. “Lonnie Ray Swartz, did with malice aforethought, and while armed with a P2000 semiautomatic pistol, kill” Jose Antonio Elena Rodriguez, the panel’s presiding juror wrote.

Border Patrol union representatives have resisted scrutiny of agents’ actions in similar cases, saying that such analysis would force agents to waste valuable seconds considering their response rather than acting to protect themselves or their fellow agents.

The National Border Patrol Council, a union that represents agents, said it would mount a vigorous defense of Swartz.

“It is unfortunate that after three years and after being investigated by multiple local, state and federal agencies and then returned to the field to work, Agent Lonnie Swartz is now facing criminal charges,” the union said in a message posted on its website.