At least eight people were killed in a shooting late on Thursday at a FedEx facility in Indianapolis, police have said.
Authorities had previously confirmed that the gunman shot and killed himself.
Multiple people were injured including four who were taken to local hospitals in the US city, police spokesperson Genae Cook said at a news conference on Friday.
One person had critical injuries. Two others were treated at the scene and released.
No law enforcement officers were injured.
The shooter wasn't immediately identified, and Cook said investigators were still in the process of conducting interviews and gathering information.
Police were called to reports of gunfire just after 11 pm and officers observed an active shooting scene, Cook said. The gunman later killed himself.
FedEx released a statement saying it is cooperating with authorities and working to get more information.
“We are aware of the tragic shooting at our FedEx Ground facility near the Indianapolis airport. Safety is our top priority, and our thoughts are with all those who are affected,” the statement said.
Family members gathered at a local hotel to await word on loved ones.
Live video from news outlets at the scene showed crime scene tape in the car park outside the facility.