ATLANTA -- The man accused of killing his 15-year-old cousin waived his first appearance in front of a Fulton County judge Wednesday morning.

Dontavious Montgomery is charged with shooting Marquez Montgomery in the head Monday night.

The 21-year-old was already out of bond on another murder charge.

Francine Montgomery was hoping to see her grandson Wednesday morning.

"This, it hurts, it double hurts," she said. "But I know that God is with me. I know that Jesus is walking with us through this."

The family insists it was an accident Monday night, when 15-year-old Marquez was shot and killed.

Their grandmother says the cousins loved each other and were very close.

"The way they portray Dontavious to be, mistakes do happen," cousin LaDarius Tinch said.

Though when asked what exactly happened that night, Tinch wouldn't elaborate.

"I don't want to talk about that," Tinch said.

This isn't the first time Dontavious Montgomery has been accused of murder. On Jan. 14 of 2015, Atlanta Police said he got in a fight with 27-year-old Nicholas Roberts at Deerfield Gardens Apartments in southwest Atlanta.

Court records show he's charged with murder, aggravated assault and tampering with evidence. He spent 9 months in jail but was granted $100,000 bond in October of the same year.

He pleaded not guilty and that trial is still ongoing.

"I know he's been in trouble - he has. But Dontavious is a good person. He loves his family," Francine Montgomery said.

Atlanta police said the gun used to kill Marquez Montgomery was stolen from Henry County.

"I did not know he had a gun," Francine said.

The grandmother added that Dontavious has received death threats since the 2015 killing.

He is expected back in court on Dec. 14 at 9:30 a.m.