Less than a month after a Border Patrol agent was killed along the U.S.-Mexico border, another person has been killed in a skirmish involving officers from the agency.

In the early hours of Wednesday morning, a 17-year-old Mexican boy named Ramses Barron Torres was killed along the Nogales, Arizona-Sonora, Mexico border by a Border Patrol agent. That much everyone agrees about. But nearly everything else about the circumstances of his death are up for debate.

Border Patrol say that agents were trying to apprehend drug smugglers along the border when Torres and his friends started throwing rocks at the agents. Torres’ friends deny that rocks were thrown and say that Torres was an innocent bystander that night.

One friend spoke with Nogales International and said the bullet that killed Torres may have been meant for him:

"I think he fired just to scare me," the youth said. But the bullet passed through the fence – the barrier at the spot where the shooting occurred consists of vertical steel tubes with several inches of space between them – and stuck Barron Torres instead.

The youth said the agent ran up behind him and grabbed him as he was trying to scale the fence back into Mexico, but let go when he started screaming that his friend had been shot.

"I think he got scared," he said.

A Mexican official said that Border Patrol agents fired warning shots after Torres and other Mexican kids tried to cross into the U.S., and that Torres died after falling from a border wall and hitting his head, the AP reported on Wednesday. The official said that no one was hit by the shots. But Nogales International reports that an autopsy conducted by the Sonoran police showed Torres was killed by a bullet that entered his body from the back of his right arm and entered his chest cavity before puncturing his lungs and getting lodged in his ribcage.

Last June another Mexican teenager, Sergio Adrian Hernandez Huereca, was shot and killed by Border Patrol at the El Paso-Juarez border. Like Torres’ death, the details of Huereca’s death were also disputed. The Border Patrol claimed Huereca and his friends were also throwing rocks at Border Patrol agents, which necessitated the use of deadly force, but then video surfaced showing that the Border Patrol agent drew his gun long before rocks were thrown. The FBI opened a civil rights investigation into Huereca’s death.

Customs and Border Patrol is the largest uniformed law enforcement agency in the United States, and their numbers only climb with the regular infusions of extra cash Congress sends for militarization of the border. Jennifer Allen, the executive director of Arizona human rights group Border Action Network, said in December that increased violence was unsurprising, given the design of decades of U.S. border security and immigration policies.

"[Violence] has been an ongoing and increasing trend that has been very predictable from the mid-1990s when the whole strategy has been based on deterrence and on making the border the most difficult to pass as possible," Allen said.