According to his family, 16-year-old Jose Antonio Elena Rodriguez was walking home from a basketball game on a main street in Nogales, Mexico on a summer night in 2012 when he was shot and killed. The shooter was a U.S. Border Patrol Agent, who was across the border in Nogales, Arizona when he fired 10 rounds -- at least eight of which struck Jose Antonio, primarily in his back -- through the border fence.

The ACLU filed a lawsuit on behalf of Jose Antonio's mother, Araceli Rodriguez, in 2014, but it wasn't until Wednesday (Sept. 23) that federal authorities officially charged the agent, Lonnie Swartz, with second-degree murder – the first time such a charge has ever been leveled in a cross-border shooting.

"The number of abuses [by Border Patrol Agents] over the past years, including fatal shootings, is startling," Lee Gelernt, Deputy Director of the ACLU's Immigrants' Rights Project  Gelernt, told MTV News. "These abuses cannot go unchecked. The Border Patrol can't continue to act with impunity."

Justice for Jose Antonio

Swartz and his lawyers allege that he shot Jose Antonio because he was among a group of "rock-throwers" who were threatening his life. The Los Angeles Times reports that “Border Patrol agents generally are allowed to use lethal force against rock-throwers because rocks can be potentially deadly. Rock-throwers have attacked agents more than 1,700 times since 2010, according to the agency."

But the ACLU alleges that neither Jose Antonio, nor anyone near him, was throwing rocks.

"We deny that Jose Antonio or anyone near him was throwing rocks," Gelernt said, "and we also now think the Justice Department has concluded likewise, given that they’ve brought second degree murder charges."

He also noted that, in the place where Jose Antonio was shot, "it would be almost impossible for Jose Antonio, even if he had been throwing rocks, to do any harm to the agent. ... So we do not believe that any agent was in danger of serious bodily harm even if there were rocks being thrown. And that's if."

Other Abuses By U.S. Border Patrol Agents

Since 2005, "on-duty Border Patrol agents and Customs and Border Protection (CBP) officers have killed at least 42 people, and in 2011-2012 alone, Border Patrol agents caused at least 15 deaths, 13 of which resulted from shootings," the ACLU notes on its website.

AZ Central reports that "in none of the 42 deaths is any agent or officer publicly known to have faced consequences — not from the Border Patrol, not from Customs and Border Protection or Homeland Security, not from the Department of Justice, and not, ultimately, from criminal or civil courts."

Even more striking is that "at least three times, agents shot unarmed teenagers in the back."

"We brought this lawsuit with other lawyers for three reasons," Gelernt said. "The first is obviously to achieve justice for this young man who was unjustifiably killed by a border patrol agent. The second reason is that we have seen systemic use of force by border patrol agents for many years, and this suit is an attempt to stop this type of abuse. The third reason is to make sure that our constitution applies across the border in cases like this."

When asked whether Jose Antonio's family could bring any charges against the agent in Mexico, Gelernt said, "The problem is that in order to enforce any judgement, they would have to have the agent extradited to Mexico. And we have seen no reason to believe from past incidents that the United States government will extradite the agent. That’s why its critical that the U.S. take action in a case like this."

Wait... What About The Constitution?

"[Swartz] and the U.S. Government have taken the position that even though the border agent was standing on the U.S. side, Jose Anotonio has no constitutional rights because he was a Mexican citizen," Gelernt explained. "We believe there should not be a constitutional-free zone along the border."

So far, it seems that a "constitutional-free zone" is exactly what exists. In a similar case from 2010, a U.S. Border Patrol Agent shot and killed 15-year-old Sergio Adrian Hernandez Guereca in Mexico across the border from Texas; a federal appeals court recently ruled that the victim's family had no constitutional rights because he wasn't a U.S. citizen.

"We have the Border Patrol saying that someone like Jose Antonio has no constitutional rights just because they were across the border," Gelernt told MTV News, "while the agents are standing on U.S. soil, with a U.S. gun shooting U.S. bullets.”

"Jose Antonio was just walking along a main thoroughfare of his town, so it's really remarkable for the agent and the U.S. government to take the position that the agent can shoot him across the border but then he has no rights to bring a lawsuit."

Gelernt said the ACLU is hopeful that the criminal indictment means that Jose Antonio's case will be different, and will mark the beginning of a change in the way the system deals with cases like his.