The attackers from the 'Panaa' gang opened fire at three youths outside a gym near Raja garden at Basti Bawa Khel locality. Previous enmity is believed to be the reason behind the incident.
While Simran died on the spot, Deepansh and Vikas were critically injured and are undergoing treatment at a local hospital.
The notorious gang is accused of killing proprietor Prince Vig in May 2012, police said.