Chief Medical Examiner Jan Gorniak told WSB-TV it sent the remains of Jeffrey Merriweather Jr. to an expert in St. Louis for evaluation in June.
"Since he was partially skeletonized, we couldn't determine a cause of death," she said.
However, the remains never made it out of state. Package tracking shows they arrived at a FedEx warehouse in Austell, but no one has seen them since, the news station reported.
Merriweather’s mother Kathleen calls it a “nightmare you can’t wake up from.”
Her husband, Jeffrey Merriweather Sr., said they had to have a funeral service without their son’s body.
"We're already dealing with the death of him," he said, "and now this. This is unacceptable to us."
Merriweather was reported missing June 12 after someone fired shots in the parking lot of an East Point McDonald’s, AJC.com previously reported.
The 31-year-old father of three went to the restaurant on Virginia Avenue the day of the shooting in a black SUV. At some point, he exited the vehicle and got into a white Toyota 4Runner. Then, someone started shooting at the Toyota, police told the news station.
Both vehicles drove off, video surveillance footage obtained by WSB-TV showed.
Merriweather was later found dead. The details of what led to his death remain unclear.
A FedEx representative said it is working with the Medical Examiner's Office to find the missing remains. Gorniak said her office is reviewing policies to make sure this doesn't happen again.
The case remains under investigation.
Anyone with information is asked to contact 678-614-7049. Tipsters can remain anonymous, and be eligible for rewards of up to $2,000, by calling Crime Stoppers Atlanta at 404-577-8477, texting information to 274637 or visiting the Crime Stoppers website.