An elderly Arizona rancher charged with murder and held on $1 million bond in connection to the shooting of a man believed to be a Mexican national on his border property, allegedly fired "warning shots" after an armed group "pointed an AK-47 right at him," his defense attorney says.

George Alan Kelly, 73, who is charged with first-degree, premeditated murder in the Jan. 30 shooting of a man whom authorities believe to be 48-year-old Gabriel Cuen-Butimea, based on the Mexican voter registration card he carried, had completed chores on his ranch near Kino Springs earlier that day and came to his house to have lunch with his wife when he heard a single gunshot as they ate, Kelly’s court-appointed attorney, Brenna Larkin, wrote in a recent court filing obtained by Fox News Digital.

Kelly saw his horse, who is old, running away scared at full speed, the filing says. 

"Finally, he saw a group of men moving through the trees around his home. They were armed with AK-47 rifles, dressed in khakis and camouflaged clothing and carrying large backpacks," Larkin wrote. "None of them were known to him. He had not given any of them permission to come onto his land."

GOFUNDME BOOTS CAMPAIGN FOR ARIZONA RANCHER HELD ON $1M BOND FOR MURDER OF MIGRANT SHOT ON PROPERTY 

Because he was "understandably concerned and reasonably feared for his safety, his wife’s safety, and his animals’ safety," Kelly called the U.S. Border Patrol ranch liaison, specifically assigned to aid people living on borderlands, to report what he had seen and "to summon immediate help," Larkin wrote.

Telling his wife to stay inside, silent and away from windows, Kelly went onto his porch with his rifle.

"The leader of the armed group of men saw Mr. Kelly and pointed an AK-47 right at him," Larkin wrote. "Mr. Kelly, fearing for his life and safety, fired several shots from his rifle, hoping to scare them away from him, his wife, his animals, and his home. As he shot, Mr. Kelly took care to aim well over the heads of the armed group of men. The group then began running into the desert surrounding his home. Once the group had fled, Mr. Kelly walked over to his barn to see if it was safe and secure."

The filing notes Kelly had a second conversation with the Border Patrol ranch liaison that ended at approximately 2:36 p.m. Even though Kelly reported that he heard a single shot and that the men he had seen were armed, the liaison "incorrectly reported" that Kelly stated he could not tell whether the men were armed or not, Larkin wrote. The radio dispatch to the Border Patrol agents en route to the property at approximately 2:40 p.m. "correctly reported that armed men had been seen in the area."

While Kelly was checking his barn, a number of Border Patrol and Santa Cruz County Sheriff's deputies arrived at the property and encountered Kelly, who indicated to them that he had seen a group of armed men near his house, the filing says. Deputies also made contact with Kelly’s wife, who indicated that she had seen armed men carrying large backpacks near the house, Larkin wrote.

Border Patrol agents and sheriff's deputies walked "all over" Kelly’s property but found no one, the filing says. They also used various cameras to try to locate the men but were unsuccessful. Law enforcement then left.

As the sun was going down later that day, Kelly went to his pastures to check on his horse, still concerned the horse might have been injured in the incident. Noticing that the dogs he took with him were focused on something on the ground near a mesquite tree, Kelly approached the area and "observed a body lying face down in the grass," Larkin wrote. He then called the Border Patrol ranch liaison a third time to report the discovery and request assistance from law enforcement.

When law enforcement arrived, Kelly helped them find the body and cooperated with their investigation, according to Larkin. The investigation found that the body was that of a male "foreign national" who did not have any firearms or backpack on his him. The cause of death appeared to be a single gunshot wound, and it appeared the body was fresh, according to the filing.

"The person [had] a radio with him, and he was wearing tactical boots, indicating he was possibly involved in illegal activity," Larkin wrote.

The defense attorney added that it remains unknown what kind of bullet caused the fatal wound, what was the time of death, how long the body had been there or where and what position the person was in prior to receiving the fatal wounds.

In an interview with law enforcement, Kelly "admitted to firing warning shots at the smugglers earlier in the day, but he denied firing any shot directly at any person," Larkin wrote. "He does not believe that any of his warning shots could have possibly hit the person or caused the death. All of the shooting that Mr. Kelly did on that date of the incident was in self-defense and justified."

Kelly and his wife have lived on their property outside Nogales, Arizona, for more than two decades. The Daily Mail previously reported that federal records show Cuen-Butimea "had a history of illegal border crossings and deportations in and around Nogales, with the most recent documented case in 2016."

Judge Emilio Velasquez has not granted Kelly’s request for a reduction of his $1 million bond despite the rancher pleading that his wife was left alone on their property and unable to attend to their livestock. A preliminary hearing is scheduled for Feb. 22 at Nogales Justice Court.

"Mr. Kelly’s … years as a law-abiding citizen, and the uncontroverted facts of the case, give us confidence in his innocence and in our ability to prove that innocence should the State continue to prosecute Mr. Kelly," Larkin said in a statement Friday obtained by AZ Central. 

GoFundMe booted all campaigns set up to raise money for Kelly, Fox News Digital previously confirmed. The Christian crowdfunding platform GiveSendGo allowed a fundraiser for Kelly to remain. It has garnered about $250,000 as of midday Sunday.

Fox News’ Adam Sabes contributed to this report.