The gang, armed with pangas and other weapons, according to the police, arrived at the shop in the middle of the night and started breaking down security door bars, to make their way into the shop.
Southern Region Police deputy spokesperson Beatrice Mikuwa said before the gang broke the main door, the final obstacle which could have granted them entrance into the shop, the businessperson, a Chinese national who was inside the shop, opened fire.
Mikuwa said the businessperson, only identified as Luwei, aged 38, intended to scare away the gang, but a stray bullet landed on one of the robbers.
The robber, according to the police, was found dead at a river bank, a kilometre away from the scene of incident after police followed blood drops.
The public in Lunzu claimed the number of robbers killed was two, but police only confirmed one.
Mikuwa said investigations were underway to trace the group and also to find out what exactly happened at the scene.
Residents said the Chinese national was under threat and his life would not have been spared if the gang had made its way into the shop.