He said when they came in they picked up two packets of potato chips and a drink before waiting inside for another customer to enter the store.
"They were looking outside and talking to the older couple who were waiting by the door and I think I heard them say something like 'are we going to run now'."
About three minutes later Mr Li said another customer came into the store and asked him for cigarettes and as soon as he communicated with the customer, the group ran.
"They ran away down towards Georges Drive and I have looked at the CCTV footage and I think it is so wrong that they were with who I think was their parents and a little baby. It makes me angry."
A police spokesperson said officers received the call at about 1pm and were making enquiries into the theft.
Just last week, mother-of-three Sehelasa Valenitaine Moala was jailed for two years and eight months after robbing the Windsor Park Store back in March with another woman.
She was charged with aggravated robbery, as well as four counts of shoplifting and one each of theft and using a document to obtain a pecuniary advantage. Approximately $4500 worth of cigarettes were stolen and $3800 worth of damage done.