A masked gang stole a money box from a security guard but escaped empty-handed when the container exploded red dye.
The robbery was at Lidl supermarket at the Weston Favell Centre in Northampton.
At some time between 8am and 8.30am on Saturday morning, a security van parked outside the store.
The guard entered the store and, as he returned to his vehicle with cash, a number of masked offenders approached him and pulled the money box away from him.
The offenders then ran off across the A43 and, as they reached the top of a bank by the side of the road, the money box exploded red dye. The money box was left on the bank and nothing was stolen.
The offenders are described as masked men or youths in dark clothing, either wearing balaclavas or hooded tops.
Witnesses to this incident, or anyone with information, should call Northamptonshire Police on 101 - alternatively, information can be given anonymously to Crimestoppers on 0800 555 111.