WASHINGTON — Sixty feet and the US-Mexico border separated the unarmed, 15-year-old Mexican youth and the US Border Patrol agent who killed him with a gunshot to the head early on a June evening in 2010.

US officials chose not to prosecute Agent Jesus Mesa Jr. and the Obama administration refused a request to extradite him so that he could face criminal charges in Mexico.

When the parents of Sergio Adrian Hernandez Guereca tried to sue Mesa in an American court for violating their son’s rights, federal judges dismissed their claims.

The Supreme Court on Tuesday is hearing the parents’ appeal, which their lawyers say is their last hope for some measure of justice.


The legal issues are different, but the Supreme Court case resembles the court battle over President Trump’s ban on travelers from seven nations in at least one sense. Courts examining both issues are weighing whether foreigners can have their day in US courts.

Privacy experts also are watching the case because it could affect how courts treat global Internet surveillance, particularly when foreigners are involved. It’s there that the ‘‘Fourth Amendment question in Hernandez seems to matter most,’’ George Washington University law professor Orin Kerr wrote on the Volokh Conspiracy blog.

The Fourth Amendment protects against unreasonable searches and seizures.

Precisely what happened in the cement culvert that separates El Paso, Texas, and Ciudad Juarez, Mexico, is in dispute, although the competing accounts are legally irrelevant to the court’s decision.

Hernandez’s family says he and his friends were playing a game that day in which they ran down the culvert from the Mexican side and up the American side to touch an 18-foot fence. Mesa arrived on a bicycle and detained one person while the others scampered back across the culvert, actually the dry bed of the Rio Grande River. He then shot Hernandez as the youth ran toward a pillar supporting an overhead rail bridge. Mesa and other agents who arrived on the scene rode away on their bikes, without checking on the youth or offering medical aid, the family says.


The Justice Department said Mesa was trying to stop ‘‘smugglers attempting an illegal border crossing’’ and fired his gun after he came under a barrage of rocks. Mesa argues in his court filings that Hernandez was among the rock throwers.

But Robert Hilliard, the family’s lawyer, said US officials met privately with the parents to explain the decision not to prosecute Mesa and told them that their son had not thrown rocks.

A cellphone video appears to show that Hernandez was running and trying to hide before he was shot.

Had Hernandez been shot a few feet to the north, he would have been on American soil and US courts would be open to his family, Hilliard said. There’s no dispute that Mesa was on the US side of the border, he said.

If the family is kept out of court, Hilliard said, the Supreme Court will be saying ‘‘that 100 percent of the conduct of a domestic police officer in the United States is unconstrained by the US Constitution.’’ The family is seeking at least $10 million, Hilliard has said.

The Trump administration, like its predecessor, is arguing that the location of Hernandez’s death, in Mexico, should be the end of the story.


The right to sue ‘‘should not be extended to aliens injured abroad,’’ the government said in its court filing.