A judge has declared a mistrial in the criminal case against 75-year-old Arizona rancher George Alan Kelly, accused of fatally shooting a migrant on his property near the U.S.-Mexico border, the court confirmed Monday night.
Jurors had been deliberating since Thursday afternoon.
Kelly was charged with second-degree murder and aggravated assault in the Jan. 30, 2023, fatal shooting of Gabriel Cuen-Buitimea, 48, a migrant who lived across the border in Nogales, Mexico. He had pleaded not guilty.
Law enforcement officials said Cuen-Buitimea was traveling with a group of migrants who ran when they saw border patrol agents in the area. Cuen-Buitimea and another migrant were allegedly heading back to the southern side of the border when they passed through Kelly's cattle ranch.
It's then that prosecutors alleged Kelly recklessly fired his AK-47 from a distance of about 115 yards, fatally striking Cuen-Buitimea in the back.
During the trial, prosecutors pointed out inconsistent statements Kelly made to law enforcement officials throughout the investigation.
According to prosecutors, Kelly initially told Jeremy Marcel -- a border patrol agent who worked as a ranch liaison -- he was returning fire after being shot at by a group of five armed individuals who were wearing packs and running southbound.
Prosecutors claimed Kelly at first failed to tell law enforcement agents he shot his weapon. Prosecutors said his story changed minutes later when he told law enforcement officials it was a group of about 10-15 people armed with AR-style rifles.
Authorities say Cuen-Buitimea was unarmed and they were unable to find evidence that another weapon had been fired.
MORE: Migrant encounters along southwest border reach all-time high of 302,000"When you see two unarmed migrants walking southbound beyond two fence lines and you take your AK-47, you walk out and don't say a word, point it at them and you shoot, would that be what a reasonable person would do in that situation?" prosecutor Mike Jette asked the jury during his closing arguments. "The answer has to be no."
Kelly's lawyers tried to poke holes in the prosecutor's account of the incident and accused law enforcement officials of failing to follow other leads that would have cleared their client of any wrongdoing. They also accused law enforcement of falsely claiming that Kelly admitted to shooting at multiple people.
"That was not true, Alan never said that. Law enforcement wasn't listening and they didn't care, they already decided that he was guilty," said defense attorney Brenna Larkin.
The defense claimed Kelly was protecting himself and his wife and only fired warning shots several yards above the group.
Authorities were not able to find the bullet that struck Cuen-Buitimea. The defense claimed he was shot by another person in the group.
Lead detective Jorge Ainza testified during the trial and told Kelly's attorneys he believed Kelly shot at Cuen-Buitimea.
"There is no other shot involved in this. The victim sustained a serious injury from a high-powered rifle, an AK-47 rifle with a trajectory directly from Mr. Kelly's residence," he said.
During the trial, jurors visited Kelly's ranch. Investigators said they found a total of 9 shell casings outside of his home that fit the pattern of shots fired in Cuen-Buitimea's direction.
Jurors also heard testimony from Daniel Ramirez, a migrant who said he was with Cuen-Buitimea who he claimed grabbed his chest and said, "I'm hit" before dying.
Ramirez testified that they were being smuggled into the United States and were not trafficking drugs. Ramirez admitted to smuggling marijuana on one previous occasion to reduce the fee he owed smugglers to get him across the border.
MORE: Supreme Court pauses strict Texas immigration law ahead of rulingKelly was charged with aggravated assault against Ramirez.
Prosecutors also showed jurors text messages allegedly sent by Kelly, which prosecution claimed showed his state of mind in the weeks before the shooting.
"OVERUN WITH DRUG CARTEL. AK GTN A LOT OF WORK," one text message read.
Court documents obtained by ABC News showed another text message exchange between Kelly and a friend on Nov. 23, 2022. The friend asked Kelly what his plans were for Thanksgiving.
"PATROLN THE BORDER 4 U NORTHENRS!" Kelly said.
"Shoot straight," the friend replied.
"OR SHOOT MANY ROUNDS!" Kelly responded.