The manager of Spar in Jukskei Park, Johannesburg, was shot dead during an armed robbery on Sunday.
Police said that about seven men entered the store just after 7pm and confronted the 50-year-old and a cashier.
The robbers shot the manager, who later died in hospital.
An undisclosed amount of money was stolen.
Police spokesperson Balan Muthan said the suspects also shot and wounded a security guard before fleeing in a security vehicle. The car was later found abandoned not far from the store.
Muthan said police had put together a special task team to hunt down the gang.