Swindon Police have released CCTV images of five men they want to speak to following an incident at Kingshill Service Station.
A force spokesperson said: "On October 24, a group of men pulled in to the garage and filled up a vehicle with petrol before one of the men paid in cash.
"Whilst this transaction took place, the other men entered the store, took several items from the shelves and put them in their pockets.
"When they were confronted by the member of staff they became aggressive and one of the men spat at the member of staff."
People with information are asked to call 101 and quote crime reference number 54220114014, or call CrimeStoppers anonymously on 0800 555 111.