Updated

The mother of a Mexican teen who was shot to death by a U.S. Border Patrol agent nearly two years ago sued the agency on Tuesday, saying her son was playing basketball with his girlfriend and friends minutes before he was hit in the back by at least eight bullets.

Jose Antonio Elena Rodriguez, 16, was in Nogales, Sonora, near the tall, steel fence that divides the United States and Mexico when a U.S. Border Patrol agent shot him from Nogales, Arizona, on Oct. 10, 2012.

The Border Patrol has said Elena Rodriguez was among a group of people throwing rocks at agents across the border, endangering their lives. The ACLU, which filed the lawsuit in federal court in Tucson on behalf of Araceli Rodriguez, says the shooting was another example of border agents using excessive force without consequences. Araceli Rodriguez says her son never had a rock or any other weapon.

The Border Patrol does not comment on pending litigation, spokesman Andy Adame said.

Agency officials in the past have defended agents' use of force.

Chief Michael Fisher said at a border expo in March that there's been a mischaracterization that agents "indiscriminately" open fire.

"If you are like me, there's nothing more terrifying than fighting for your life when you're alone with no communication, and the thought for a split second that you may never get home at the end of that shift to see your wife and son again," Fisher said. "The only thing that is equal to the ripple of fear is thinking of having to use deadly force against another human being."

Immigrant rights groups have long claimed that agents are trigger-happy.

In the lawsuit, the ACLU alleges that the border patrol has a "systematic" problem with use of force.

"Jose Antonio's killing by U.S. Border Patrol agents is unfortunately not a unique event, but part of a larger problem of abuse by border patrol agents in Nogales and elsewhere," the lawsuit states.

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