He then committed suicide, the local media are saying today.
A fierce altercation over a market stall preceded the tragedy, according to the reports.
Belgrade Emergency Medical Services spokeswoman Nada Macura told Tanjug that a man in his 40s was pronounced dead. He had a gunshot wound to his chest and is presumed to have been murdered, she explained.
Another man, in his 50s - believed to have been the killer - was also pronounced dead. Macura said that the exit wound was at the top of his head, and that doctors assume that he shot himself in the mouth.
The police are investigating the scene.