The other officers returned fire and pulled Toney to cover, and the suspect vehicle sped off.
According to the Gwinnett Daily Post, Maynard is 18 years old.
A second suspect, Isaiah Pretlow, 19, was charged with aggravated assault related to a separate incident following Toney's fatal shooting, police said. He was taken into custody by U.S. Marshals about 11:30 p.m. He faces charges of aggravated assault and felony murder.
Shots were fired at the officer from inside the auto, police said. An officer who was searching the area encountered Pretlow about 3 p.m. Police say Pretlow pointed a gun at the officer, who fired shots.
The shooting happened near Shiloh Middle School, about 25 miles (40 kilometers) northeast of Atlanta.
As many as four suspects are believed to have fled the crash scene on foot. It's unclear if any of the suspects are injured.
Multiple people have been interviewed about their possible involvement in the shooting, but no formal charges have been filed, police said. Toney was a two-year veteran of the department.
Police have not released details about Toney's injuries and have not said whether anyone in the suspects' vehicle was hit or how many shots were fired.
Upon finding and nearing the vehicle, "shots were fired from inside the suspect vehicle", and one of them hit Toney, the news release said. Tributes, words of comfort, and memorials were posted to the social media accounts of numerous law enforcement agencies in Georgia by late Saturday.
WSB-TV reporter Rikki Klaus tweeted Saturday night that authorities had surrounded a nearby residence and were waiting for a search warrant.
Toney, who was originally from Southern California, had been with the department for nearly three years.
Fox4KC reports "there were as many as four people inside the vehicle".
Thomas indicates that suspect's vehicle was on "Crumps Landing behind Shiloh Middle School" when Toney approached it.