The men are each charged with felony murder, theft by receiving stolen property, multiple counts of aggravated assault, armed robbery, and second-degree criminal damage of property, Clayton County jail records show.
Both were denied bond during their first appearance Thursday.
Police said the shotgun used in the shooting was reported stolen in 2012 in Cobb County.
Investigators canvasing the community were able to track down Gomez, and he eventually pointed them to Alvear, Robinson said.
“The shooter actually finally confessed to the incident and implicated the other gentleman being there, also,” Robinson said.
Steven was outside around 10:30 p.m. Monday helping his sister prepare the truck her boyfriend gave her for its first official drive.
Samaria Diaz said a she had just gotten the customized Chevrolet Silverado registered and insured earlier that day.
“Steven had just put the (license) tag on and was putting air in the tires for me,” she said.
Police say the special butterfly doors, that swing up to open rather and out, is what attracted the would-be car thieves.
“Because of the doors on the truck, they thought they would enjoy the vehicle,” Robinson said.
Diaz said the men drove up in a burgundy SUV, snatching her necklaces and demanding cash and her truck keys at gunpoint.
Alvear tried to drive the truck away, but it wouldn’t start, police said.
“One raised his shotgun at the truck and fired,” Diaz said. “The other one started hitting the truck and smashing the window with a baseball bat.”
Diaz said she and her brother had been backing away from the gunman when Steven was hit.
“He shouted, ‘I’ve been shot,’” Diaz said. “I was holding him in my arms when he died.”
Diaz’s other brother, Jose Diaz, heard the gunfire and came outside.
When he tried to confront the men, the gunman aimed the gun at him.
“But when he pulled the trigger … the gun didn’t fire,” Dominique Rodriguez, Jose Diaz’s girlfriend, told The Atlanta Journal-Constitution. “Then they drove away.”
Robinson said neither Alvear nor Gomez seemed sorry that a child died because of their actions.
“Everything at this point indicates that they did know that they shot the kid,” Robinson said. “There has not been any remorse shown at this point.”
Investigators believe there may be another suspect who remains at large.
“We do have some leads, and it is a great possibility that a third suspect is involved,” Robinson said.
The investigation continues.
The Chik-fil-A franchise at 4959 Jonesboro Road in Forest Park will host a fund raising drive called “Dollars for Diaz” on Wednesday from 4 to 9 p.m. to serve as a point of collection for people wanting to donate money to help pay for Steven’s funeral and burial costs.
A portion of the restaurant sales from the day will go towards the costs as well, restaurant officials said.
A yard sale will be held Saturday starting at 9 a.m., at the soccer field behind Living Faith Tabernacle at 5880 Old Dixie Road, adjacent to the apartment complex where Steven was shot.