Robbers threatened staff with a hammer and handgun and stole a cash box at a supermarket in Chorlton.
It happened at about 1.55pm on Wednesday 9 April 2014, when two men wearing dark clothing and motorbike helmets walked into the Co-op on Barlow Moor Road.
They threatened security staff who were making a cash delivery to an ATM inside the shop, the robbers grabbed the cash box and ran out of the supermarket.
They left on a motorbike in an unknown direction.
Detective Constable Mark Evans from South Manchester division, said: â€œDid you witness the robbery or see the offenders fleeing on a motorbike? Do you know who is responsible or have heard anyone bragging about the incident? If so please call us.
â€œI am also eager to hear from anyone who saw a motorbike near to the Co-op before the robbery or saw it travelling at speed in the Chorlton area.
â€œThe threats towards the staff have left them shaken but thankfully they were not physically injured and they can be reassured we will do all we can to identify the offenders.â€
Anyone with any information is asked to contact police onÂ 0161 856 6094Â / 101, or Crimestoppers, anonymously, onÂ 0800 555 111.