The place where in 2010 Mexican 15-year-old Sergio Hernandez was killed by a police officer from the United States on the Mexican bank of the Rio Grande in Ciudad Juarez, Chihuahua, Mexico. (Photo: YURI CORTEZ via Getty Images)

The Supreme Court on Monday declined to decide on whether non-citizens have constitutional rights at the border, and ordered the U.S. Court of Appeals for the 5th Circuit to reconsider the question of whether the families of Mexican nationals killed by U.S. border authorities can sue in federal court.

The lower court will again decide whether the family of Sergio Hernandez, a 15-year-old Mexican national fatally shot by a U.S. border patrol agent near the U.S.-Mexico border in 2010, has the right to sue the agent. Previously, the 5th Circuit found that Hernandez didn’t have constitutional protections.

On Monday, the Supreme Court vacated that ruling and ordered the lower court to reconsider the case.

“The facts alleged in the complaint depict a disturbing incident resulting in a heartbreaking loss of life. Whether petitioners may recover damages for that loss in this suit depends on questions that are best answered by the Court of Appeals in the first instance,” reads the ruling.

Three justices dissented: Clarence Thomas, who was in favor of upholding the lower court ruling, and Steven Breyer and Ruth Bader Ginsburg, who in a joint dissent penned by Breyer said they would reverse the lower court ruling with regards to the Fourth Amendment question and allow the Hernandez family to seek damages.

Because oral arguments were heard prior to Justice Neil Gorsuch joining the Supreme Court, just eight justices considered the case.

On July 7, 2010, Hernandez was playing with friends along the Rio Grande, between the U.S. city of El Paso, Texas, and the Mexican city of Ciudad Juárez. A U.S. Border Patrol agent, Jesús Mesa Jr, saw the boys and assumed they were attempting to illegally cross the border. Mesa grabbed one boy, but others fled. A Justice Department investigation found that some of the boys began to “hurl rocks” at Mesa. (There is no evidence that Hernandez threw anything at Mesa.) Mesa then saw Hernandez, who was taking cover behind a bridge on the Mexican side of the river, and shot him in the face, killing him.

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The Justice Department declined to prosecute Mesa in 2012, arguing that he acted in self-defense. The U.S. government declined to extradite him to Mexico for prosecution.

A civil liability claim is the family’s last option in seeking justice for the killing. Hernandez’s parents, María Guadalupe Güereca and Jesús Hernandez, sued Mesa in federal court with the help of a Texas law firm, arguing that the agent violated their son’s constitutional rights.

Federal judges repeatedly rejected the family’s claims, saying the Constitution does not apply to a non-citizen not on U.S. soil. Those rejections relied on a 1990 Supreme Court ruling, United States v. Verdugo-Urquidez, that found non-citizens must have a “substantial connection” to the U.S. in order to be granted constitutional protections while in a foreign country. (Another key Supreme Court decision, Boumediene v. Bush, found in 2007 that foreign-born detainees held at Guantanmo Bay have due-process rights to challenge their detentions.)

There was no specific legal standard, however, for whether constitutional rights apply in cross-border situations involving non-citizens. If Hernandez was a U.S. citizen, his constitutional rights would be assured, no matter where he was at the time of the shooting. And he would have been afforded those same rights had the shooting occurred on the U.S. side of the river.

But because the shooting took place in what lawyers representing Hernandez’s family described as “a unique no-man’s land—a law-free zone in which U.S. agents can kill innocent civilians with impunity,” Hernandez’s rights were murky.

In 2015, the U.S. Court of Appeals for the 5th Circuit sided with Mesa, concluding that because Hernandez was on Mexican soil and was “a Mexican citizen who had no significant voluntary connection,” he had no U.S. constitutional protections.

Last year, the Supreme Court agreed to take on the case. The court heard oral arguments in February, appearing split over whether the Constitution should apply in cross-border situations.

Justice Department lawyers argued that the matter shouldn’t be for courts to decide, due to foreign-policy implications.

“You have a cross-border incident, which necessarily gives rise to foreign-relations problems, which are committed to the political branches,” Justice Department lawyer Edwin Kneedler argued.

The justices, meanwhile, grappled with how to establish a standard narrow enough to not open up the U.S. government to civil liability for other incidents on foreign soil.

“How do you analyze the case of a drone strike in Iraq, where the plane is piloted from Nevada?” Chief Justice John Roberts asked Hilliard during arguments. “Why wouldn’t the same analysis apply in that case?”

But Hilliard, the attorney representing Hernandez’s parents, argued that the standard could be specific enough to not apply to military operations. Domestic law enforcement officers, such as Border Patrol agents, should be subject to the Constitution, he argued.

“Right now, while they’re in the United States, their boots never leave the country, and it’s the government’s position that the Constitution turns off like a light switch at the border, and they are unconstrained by our U.S. Constitution,” Hilliard said.

Read more background of the case here.

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U.S. Supreme Court Justice Anthony Kennedy (bottom 2nd L) reacts while chatting with Chief Justice John Roberts (C) during a new U.S. Supreme Court family photo including Justice Neil Gorsuch (top R), their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017. Also pictured are Justice Ruth Bader Ginsburg (front row, L-R), Justice Clarence Thomas, Justice Stephen Breyer, Justice Elena Kagan (back row, L-R), Justice Samuel Alito and Justice Sonia Sotomayor.

U.S. Chief Justice John Roberts (seated C) leads Justice Ruth Bader Ginsburg (front row, L-R), Justice Anthony Kennedy, Justice Clarence Thomas, Justice Stephen Breyer, Justice Elena Kagan (back row, L-R), Justice Samuel Alito, Justice Sonia Sotomayor, and Justice Neil Gorsuch in taking a new family photo including Gorsuch, their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

U.S. Supreme Court Justice Anthony Kennedy (bottom L) chats with Chief Justice John Roberts (bottom R) during a new U.S. Supreme Court family photo including Justice Neil Gorsuch (not pictured), their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017. Also pictured are Justice Elena Kagan (back row, L-R), Justice Samuel Alito and Justice Sonia Sotomayor. REUTERS/Jonathan Ernst

U.S. Chief Justice John Roberts (seated L-R), Justice Clarence Thomas, Justice Stephen Breyer, Justice Sonia Sotomayor (top L) and Justice Neil Gorsuch (top R) chat during a new U.S. Supreme Court family photo including Gorsuch, their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

U.S. Supreme Court Justice Anthony Kennedy (L) chats with Chief Justice John Roberts (R) during a new U.S. Supreme Court family photo including Justice Neil Gorsuch (not pictured), their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

U.S. Justice Neil Gorsuch (top R) leans in to speak to Justice Stephen Breyer (bottom R) as the members of the U.S. Supreme Court including Chief Justice John Roberts (seated L), Justice Clarence Thomas (seated C) and Justice Sonia Sotomayor (top L) gather for a new family photo with Gorsuch, their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

U.S. Chief Justice John Roberts (seated C) leads Justice Ruth Bader Ginsburg (front row, L-R), Justice Anthony Kennedy, Justice Clarence Thomas, Justice Stephen Breyer, Justice Elena Kagan (back row, L-R), Justice Samuel Alito, Justice Sonia Sotomayor, and Justice Neil Gorsuch in taking a new family photo including Gorsuch, their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

U.S. Chief Justice John Roberts (seated C) leads Justice Ruth Bader Ginsburg (front row, L-R), Justice Anthony Kennedy, Justice Clarence Thomas, Justice Stephen Breyer, Justice Elena Kagan (back row, L-R), Justice Samuel Alito, Justice Sonia Sotomayor, and Justice Neil Gorsuch in taking a new family photo including Gorsuch, their most recent addition, at the Supreme Court building in Washington, D.C., U.S., June 1, 2017.

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This article originally appeared on HuffPost.