Homicide detectives are investigating the death of a man found wandering along I-20 with a gunshot wound early Tuesday.

Atlanta police Capt. Adam Lee III told the AJC that some "good Samaritans" picked up the victim, who was trying to flag down cars on I-20 westbound near the Fairburn Road overpass around 2 a.m.

"He was in a lane of traffic," Lee said.  "They told us that several other cars had swerved to avoid striking him."

The victim "asked if they could help him, that he had been shot," Lee said.

He said the passersby called 911 and took the man to a BP station on nearby Fulton Industrial Boulevard.

A Grady Memorial Hospital ambulance met them at the BP and took the man to Grady, where he later died.

The victim's name has not been released, but Lee said he was in his early 20s.

Lee said the man might have at one time been in a car that was found in the emergency lane near where he was picked up.

"There was a vehicle there," he said. "We don't know for a fact that he was driving the vehicle. He was near the vehicle when the good Samaritans picked him up."

Lee said investigators "don't have any idea where he was shot. He was found shot at that location, but we don't have any evidence that he was shot there on the expressway."