Four armed men came on two bikes at the trader's establishment yesterday and looted Rs 1.5 lakh cash from his shop, they said.
When the guard and the cashier, identified as Sunil and Harprit respectively, offered resistance they were fired upon in which Sunil was killed and Harprit was injured.
A case has been registered in this regard and a hunt to nab the robbers is on, the police said.