Six people were recovering Tuesday after police say a gunman opened fire at a FedEx facility in Kennesaw, just north of Atlanta. According to investigators, the unidentified shooter was a FedEx employee.

Two of the victims were in critical condition as of 4:00 Tuesday afternoon. Dr. Michael Nitzken, an emergency room physician at WellStar Kennestone Hospital in Marietta, said all of the victims sustained multiple gunshot wounds, consistent with shotgun blasts.

“Assault rifles and higher caliber wounds are more damaging," said Nitzken. "The direct blast of the shotgun is always concerning. I believe that some of these other ones were mainly peripheral damage.”

Doctors released two of the victims Tuesday, but Dr. Nitzken said the other four would likely need hospitalization. Around noon, two were still in life-threatening condition.

“With two critical people still in surgery, I would still say that there is quite a bit of work still to do for them,” explained Dr. Nitzken.

So far, investigators have not released the shooter’s name or a possible motive. Cobb County Police Sgt. Dana Pierce said that information would likely not be released Tuesday because the FedEx location is still being treated as a crime scene.

“They’re going to process it as they normally would,” Sgt. Pierce said. “But it is a process.”

FedEx released a short statement about the shooting:

“We can confirm that an incident occurred early Tuesday morning at a FedEx Ground facility in Kennesaw, Georgia. Our thoughts and prayers are with those affected, and with their families and friends. We are grateful for the assistance of law enforcement. The situation is now stabilized and we are focused on the needs of our team members and cooperating with the law enforcement investigation of this tragedy.”

The shipping company plans to release any further statements on its website at news.fedex.com.

Tags: hospital, Cobb County, shooting, Kennesaw, FedEx, victims, WellStar, shotgun, Kennestone, Dr. Michael Nitzken