Two thieves walked into Morrisons in Northampton and grabbed handfuls of Amazon gift cards.
They hid the gift cards in their coat pockets during the theft at the supermarket in Victoria Promenade which happened on Wednesday last week.
A spokesman for Northamptonshire Police said: “When they were challenged by security and staff, they put some of the gift cards back, but then assaulted two members of staff by punching them to the face several times.
“They then made off with some of the gift cards.”
One of the offenders is described as black, of large build, with short black hair, wearing a black top, a large dark green coat with red lining and black trousers.
The second offender is described as black, of slim build, with short black hair, wearing a tight fitting, black leather jacket and black trousers.
The incident happened sometime between 9 and 10pm on Wednesday, November 25.
Anyone with any information can call Northamptonshire Police on 101. Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.