A BMX bike was stolen from outside a fish and chip shop in Churchill Way, Burton Latimer.
Two men walked past the bike, which had been left outside the back of the shop, when one of them turned back, got on the bike and rode off down an alleyway towards High Street.
The second man continued walking towards Churchill Way.
The theft happened at about 1.30pm on Friday, January 29.
The suspect was white and was wearing a navy jacket, dark trousers and blue footwear.
The second man was black and was wearing dark clothing.
The bike was mainly black, with some pink in the middle of the handle bars and wheels.
It had WeThePeople stickers on it.
Witnesses to the incident, or anyone with information about the stolen bike, are asked to call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.