SAN ANTONIO – A 75-year-old man and his 14-year-old grandson were arrested in connection with the September shooting death of a 13-year-old boy in north Bexar County, Sheriff Javier Salazar said Monday.

"I have nothing to say. I don't even know nothing what's going on," Robert Lee Voigt told reporters as he was led by sheriff's deputies to a county vehicle.

Salazar said that Voigt had previously purchased an AR-15-style semi-automatic rifle for his grandson as a gift.

Related: Officials ID 13-year-old boy killed by gunshot to head; authorities still investigating

Around 3 p.m. Sept. 28, the grandson cleaned the weapon and took it to an RV behind the grandfather's home in the 900 block of Pine Eagle Lane, Salazar said. The 14-year-old lived in the RV.

Inside the RV was Ignacio Romo and other friends, and at some point, the 14-year-old pointed the rifle at Romo's head and fatally shot him, Salazar said.

“For it to happen close by in our neighborhood, I was as ... shocked as anyone would be that that would happen to children in their neighborhood," said Bill Bancker, a neighbor.

Bancker said he is familiar with the pain of losing a loved one this way.

“I have firsthand knowledge of it due to something that (happened) with my nephew when he was 12 years old," Bancker said. “I don't think they have a complete understanding of -- first of all -- how a gun works or actually how deadly they can be. They see that on TV and it kind of desensitizes them to where they are not thinking about it when they are playing with them."

The 14-year-old called 911 and told dispatchers that Ramos had shot himself in the head, Salazar said. But the investigation revealed that the teen was lying.

Voigt is charged with making a firearm accessible to a child involving serious bodily injury or death, a Class A misdemeanor. His grandson is charged with manslaughter and is being held at the Juvenile Detention Center.

"The fact that a 13-year-old and 14-year-old were left unsupervised with any weapon, even more so, with a high capacity mag and very, very powerful ammunition to the point where a 13-year-old who was fine one minute and now is dead and gone the next minute -- I think that certainly demonstrates that this is irresponsible gun ownership times 10," Salazar said.

Bancker said he hopes this situation stresses the importance of parents teaching their children about gun safety and supervising them while handling weapons.

“I would just highly suggest to parents -- take the necessary precautionary measures in locking and concealing and securing their weapons," Bancker said.

He said if he had any advice for the family dealing with this loss, he believes trusting in God will help.

“The only way we overcame something like that was putting our faith in the Lord and savior, Jesus Christ," Bancker said. "Let God help you through this process and take everything a day at a time. Allow him to extend his love and grace to you through this hard time."