A shop assistant was threatened with a knife while the offender demanded cash during an armed robbery at McColls newsagents in the Danesholme Centre, Corby.
The shop assistant quickly closed the till but the offender made off with a box of coins and rode away on a bike on on Saturday, August 6.
The offender wore grey Adidas track-suit bottoms with blue stripes on the sides, a grey top, a red and white baseball cap and dark shoes with white soles.
Officers would like to identify the person in this CCTV image and anybody who thinks they recognise this person is asked to contact police.
Witnesses or anyone with information about the knifepoint robbery can call police on 101 or Crimestoppers anonymously on 0800 555111.