A group of four men on two motorcycles allegedly tried to rob a woman at gunpoint and opened fire at a man who had tried to help her at Mahamayatala, a neighbourhood near Garia, on Friday.
One of the four was dragged off the bike by residents while the others fled.
Police said one improvised single-shot gun and three live cartridges were seized from him.
Shyamali Chakraborty, a resident of Laskarpur under Narendrapur police station, was heading for bank in Mahamayatala at 3pm when the men tried to snatch her bag.
“One of them pointed a gun and snatched my bag before kicking me. Some people in the area saw that and one of them tried to help me. One of the snatchers opened fire towards him,” Shyamali said.
People who had gathered at the spot managed to get hold of one of them and dragged him off the motorbike.
Superintendent of police, Baruipur police district, Palash Dhali, said: “One round has been fired. No one has been injured”.
The police identified the accused as Suraj Sheikh, a resident of Budge Budge.