A narcotics traffic stop on the Downtown Connector turned deadly Saturday afternoon when a man climbed over the interstate railing, fell about 35 feet and was decapitated on a wrought-iron fence, Atlanta police said.

Officers in a marked car stopped the man about 4:30 p.m., as he drove south on the interstate above Auburn Avenue. The man, who has not been identified, stopped his vehicle and tried to flee by climbing over the railing, Lt. Danny Agan said.

Police still are investigating whether the man jumped or fell off the raised interstate.

"This is a new one for me in 29 years," Agan said.

The decapitation shocked people who work in the neighborhood. Gary White, an income tax preparer, came out of his office when he heard the commotion. "It's surreal," White said.

Agan said narcotics officers had been trailing the man for much of the day.

Agan did not know if the officers who tried to arrest the man would be placed on administrative leave. "This is not something normally covered under the [standard operating procedure] of the department," he said.