The GBI is expediting tests on a rifle recovered Friday from the scene of three shooting deaths in Dooly County.
Ballistics work on the weapon is a priority in determining what happened, said J.T. Ricketson, special agent in charge of the GBI's Perry office.
"There are community concerns," Ricketson said Monday as evidence was on its way to the state crime lab.
Investigators are trying to determine whether a killer is still on the loose or possibly died on Hill Street.
When sheriff's deputies arrived after 4:15 a.m. Friday, they found a woman and 17-month-old boy with fatal gunshot wounds.
Priscilla Adams, 37, died in the ambulance, and her son's girlfriend's toddler also was dead at the scene. Adams' 17-year-old daughter sustained gunshot wounds and was rushed to Macon's Medical Center, Navicent Health, to be treated for her injuries.
Later in the morning, K9 trackers found 60-year-old Willie James Merrell dead of a gunshot wound to the torso near his house across the street from the other victims.
Authorities recovered a weapon near Merrell's body.
"We collected a rifle that matches the shell casings," Ricketson said.
It's possible Merrell shot the others before turning the rifle on himself.
"We can't make that leap until we have further analysis of the evidence," Ricketson said.
Although testing is being expedited, Ricketson could not estimate when the results could be ready.
Neighbors told investigators they were not aware of any disputes between Merrell and Adams.
The GBI and Dooly County Sheriff's Office are "actively working" the case and still conducting interviews.