(CNN)On October 10, 2012, shortly before midnight, 16-year-old José Antonio Elena Rodríguez took a walk.
The US agent who killed a Mexican teen across the border isn't immune from a lawsuit, court rules
It was a peaceful walk along the Calle Internacional, which runs parallel to the US-Mexico border. Then, without warning, the bullets came.
And they kept coming, between 14 and 30 of them, all from the Nogales, Arizona, side of the border. About 10 of those bullets hit José, most of them in the back, and killed him.
They came from US Border Patrol Agent Lonnie Swartz, who aimed his pistol at the teen through the border fence.
The teen's mother, Araceli Rodríguez, sued Swartz for violating her son's constitutional rights. When the agent appealed on the grounds of qualified immunity, the courts were left to decide if the suit should stand.
A federal appeals court's verdict: The Mexican boy died on Mexican soil. But he still deserved to be constitutionally protected against Swartz's use of deadly force.
And because of that, the US Court of Appeals for the 5th Circuit held Tuesday, the mother's claim can proceed.
Swartz said he shot through the fence because he was getting attacked by rock throwers and feared for his life, the Arizona Republic reported. But the court determined the teen wasn't doing anything wrong.
"He did not throw rocks or engage in any violence or threatening behavior against anyone or anything," according to the court's ruling. "He was just walking down a street in Mexico."
José's mother sued Swartz for damages, saying he violated the Fourth and Fifth Amendments in the killing of her son.
Swartz challenged the court, claiming he had qualified immunity. This protects public officials from being sued for damages, but they can be sued if they violated a clearly established federal or constitutional right.
On the count of qualified immunity, the court said no. Officers should know not to kill unless someone poses an immediate threat, and they have to give the suspect a warning.
Swartz didn't do either of these things, Judge Andrew Kleinfeld wrote in the court's opinion.
"It is inconceivable that any reasonable officer could have thought that he or she could kill J.A. for no reason," Kleinfeld wrote.
Swartz also argued the Constitution doesn't protect José, who wasn't a US citizen and who wasn't shot in US territory.
The court's response: Swartz couldn't have known whether José was an American citizen when he shot him. Also, his unreasonable use of force took place on American soil.
"Just as Mexican law controls what people do there, American law controls what people do here," the ruling says.
In April, Swartz was acquitted of second-degree murder charges in José's death, but the jury was deadlocked on voluntary and involuntary manslaughter. Swartz's retrial is set for October.
The American Civil Liberties Union argued the federal appeals court case. Lee Gelernt, deputy director of the organization's Immigrants' Rights Project, said the ruling sends a clear message.
"The ruling could not have come at a more important time, when this administration is seeking to further militarize the border."
While the court ruled that the shooting was completely unjustified, Kleinfeld said it's possible things could shift.
If the teen's mother's story is unsupported, or when all the facts of the incident come out, he wrote, it's possible a court could arrive at a different conclusion.
"When all of the facts have been exposed, the shooting may turn out to have been excusable or justified," he wrote.
Courts have faced similar decisions in cases surrounding the border.
In 2010, a 15-year-old Mexican boy, Sergio Adrian Hernandez Guereca, was playing with friends on the cement culvert that separates Texas from Mexico. A US Border Patrol agent shot and killed Hernandez.
The boy's parents sued the agent six months later, but the court's ruling looked a bit different.
In that case, a federal appeals court said Hernandez did not get constitutional protections on the other side of the border. And because of that, it said, his family couldn't sue the agent for violating his rights.