The federal Bureau of Alcohol, Tobacco, Firearms and Explosives will try to obtain leads from the weapon, a Marlin .22-caliber rifle, Clayton County police Officer Phong Nguyen said.
More than 50 officers spent Wednesday afternoon going door-to-door in the neighborhood where witnesses saw the man aiming at the bus Monday morning, The Atlanta Journal-Constitution reported.
Police recovered the rifle and a notebook filled with bus numbers at the scene.
Codarrius Brewer and his uncle were outside when they spotted the man.
"He wasn't really hiding," Brewer, 20, told the Journal-Constitution. "At first we were just trying to figure out what he was doing."
When it became clear the man was aiming a rifle at a school bus, Brewer said he yelled out and the man dropped his rifle and fled. Brewer said he chased the man until the suspect drew a second gun and fired at him. He wasn't hurt. The gunshot left a hole in a wooden fence.
Buses carrying students to and from six schools are getting extra police protection. The plan is to continue the police escorts through Friday, which is the last day of the school year, Nguyen said.
"I've been staying inside," Lovejoy Middle School student Takenya Varner told CBS Atlanta. "I'm making sure my mom's watching over me and making sure I don't come outside by myself."
Varner's classmate Austin Astwood said the extra police protection was comforting.
"But it still makes me nervous because they haven't found him yet, so it's still kind of nerve-wracking."
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