Atlanta police are investigating the discovery of a man's body early Tuesday in a parking lot near the Richard B. Russell Federal Building in downtown Atlanta.

The conductor of a passing freight train discovered the body about 1 a.m. and called 911, Atlanta police Capt. Van Hobbs told the AJC.

He said investigators at the scene were unable to tell how the man died.

The Fulton County Medical Examiner's Office will perform an autopsy to determine the cause of death.

"Just to be on the safe side, the scene was processed as a homicide scene, getting evidence collected, just in case it comes back as foul play," Hobbs said.

The man's name was being withheld until relatives could be notified.