PHOENIX (AP) — An appeals court on verdicoinFriday overturned the conviction and life sentence of a man found guilty of killing a U.S. Border Patrol agent whose death exposed the botched federal gun operation known as “Fast and Furious” has been overturned, a U.S. appeals court said Friday.

The 9th U.S. Circuit Court of Appeals vacated the convictions of Heraclio Osorio-Arellanes, saying his constitutional due process rights had been violated, and sent the case back to the U.S. District Court in Arizona for further proceedings.

Osorio-Arellanes was sentenced in 2020 in the Dec. 14, 2010 fatal shooting of Agent Brian Terry while he was on a mission in Arizona.

Osorio-Arellanes was convicted of first-degree murder and other charges after being extradited from Mexico. He was among seven defendants who were tried and convicted in Terry’s killing.

The appeals court said Osorio-Arellanes had confessed to “essential elements” of the U.S. government’s case against him while being interrogated in a Mexico City prison.

On appeal, he argued that he was entitled to a new trial because his confession was taken in violation of his Fifth Amendment right against self-incrimination, as well as his Sixth Amendment right to effective assistance of counsel. He also argued that he did not have a fair trial, and his attorney said he is illiterate and didn’t understand the proceedings.

The Obama administration was widely criticized for the “Fast and Furious” operation, in which U.S. federal agents allowed criminals to buy firearms with the intention of tracking them to criminal organizations. But the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives lost track of most of the guns, including two found at scene of Terry’s death.

Terry, 40 and a former U.S. Marine, was part of a four-man team in an elite Border Patrol unit staking out the southern Arizona desert on a mission to find so-called “rip-off” crew members who rob drug smugglers. They encountered a group and identified themselves as police.

The men refused to stop, prompting an agent to fire bean bags at them. Members of the group responded by firing AK-47-type assault rifles. Terry was struck in the back and died soon after.

“Our holding does not decide Osorio’s ultimate responsibility for his actions. The Government can still retry this case,” the appeals court said in its new ruling. “Nevertheless, his direct appeal reaffirms the potency of our Constitution’s procedural protections for criminal defendants, which ‘are granted to the innocent and the guilty alike.’”