Brother killed at OK Foods for *****ing 3 air freshners

On Tuesday the the 24th of October 2023,my brother stole 3 car airfreshners at OK foods in phumula ext 21 rooderkop,he was then caught by the security at OK foods they bit him until he was unconscious,we then took him to the hospital where he passed on the 27th October 2023 due to the injuries,I'm not saying my brother is right by *****ing,but what does South African law say about someone whose caught *****ing,don't they hold him and call the police,what gives them the right to kill,please help us as a family