A 13-year-old boy was shot dead while sleeping over at a friend's house after a gunman riddled a Georgia home with dozens of bullets in a horrifying overnight attack that also killed a 45-year-old man.

Demarcus Shirley had been spending the night with several other boys inside the DeKalb County home when the gunfire erupted shortly before dawn on July 2.  

Investigators say dozens of rounds were fired into the house striking the teen, Demarcus and the older man, Chauncey Newman, who were both pronounced dead.

Miraculously, the other children inside the home escaped without physical injuries.

Days later authorities announced a major breakthrough in the case and police arrested 21-year-old Keyshun Webb, who now faces two murder charges as investigators probe what they believe was likely a gang-related shooting.

DeKalb County Sheriff's Office confirmed Webb was arrested on July 7 in connection with the deadly shooting.

He is being held without bond at the DeKalb County Jail and faces two counts of murder, eight counts of aggravated assault with a weapon and one count of cruelty to animals.

According to arrest warrants obtained by Atlanta News First, investigators believe Webb was also involved in another drive-by shooting on the same day.

Authorities said shell casings recovered from both crime scenes matched, and investigators determined gang involvement was 'likely.'

Police believe two vehicles carrying four male suspects were involved in the shootings, although no additional arrests have been announced.

As detectives continue piecing together the attack, friends and relatives are remembering Demarcus as an energetic teenager whose life was cut tragically short.

'He seemed eager to learn. Kind of athletic,' his great-uncle, Gregory Carthon, told Atlanta News First. 'He had a lot of life in front of him.'

Heartbreaking video shared by family members showed Demarcus smiling and enjoying Father's Day celebrations with loved ones little more than a week before he was killed. 

For the boys who survived the shooting, the trauma remains overwhelming.

Larenzo Pinkins, who had been sleeping inside the house, recalled the horrifying moment he discovered his friend.

'We had come upstairs, and I had seen him, and I tried to grab him, and he was dead. Demarcus,' Pinkins told 11Alive.

Consumed by grief, he struggled to explain why he wished he could have taken his friend's place.

'I'm happy it wasn't me. I'm happy I wasn't hit, but it should've been me, though, before Demarcus,' he said. 'Demarcus had too much life to live. He died too young.'

Another boy who survived the attack, Larry Bell-Ware, said Demarcus had no connection to violence.

'He wasn't in the streets at all,' Bell-Ware said. 'He's just a funny little kid who liked to run around and play like a normal little kid.'

Pinkins said the pair had become inseparable.

'He was really like my little brother for real. I've been with him every day for like two months,' he told 11Alive.

The children also remembered Newman, whose home had become a safe haven for neighborhood youngsters.

Bell-Ware said Newman never turned children away if they needed somewhere to spend time.

'He let us come over there when we had nowhere to go. Anybody,' Bell-Ware said. 'Any kids who were ever just walking around and didn't have anywhere to go, they could just come here. He was just a good person in general.'

Authorities have not publicly disclosed what investigators believe sparked the fatal shooting.

The investigation remains ongoing as detectives work to identify the remaining suspects they believe were involved.