Two men stole a large quantity of cash from McColl’s newsagents in Danesholme Centre, Corby, after threatening staff with crow bars.
The incident happened on Saturday, 4 June at about 5.15pm.
The two offenders, believed to be male, were using bikes.
Both wore black, hooded tops. One wore faded jeans, a dark-blue and yellow scarf and carried a bag.
The other wore dark grey jogging bottoms and a baseball cap with a light coloured peak.
Members of the public were attempting to enter the store while the robbery took place and officers are appealing for these people to contact police as they are key witnesses.
Anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 555 111.