Officers investigating the robbery of a HSBC branch in Cambridge have released an artist's impression of the man based on witnesses' descriptions.
At 2.35pm on September 19 a man entered the bank in St Andrew's Street where he demanded money and threatened staff.
The cashier of the branch of HSBC believed the man had a weapon, so handed over about £500 of cash, then left the bank on foot.
At the time Cambridgeshire police said there was a weapon mentioned in the theft, but no weapon was actually seen during the incident.
A spokeswomen for the police at the time said: "They said they had a gun in their bag, but no one saw it [and] it wasn't brandished."
Police remained at the scene into the evening, but the bank did reopen the next day.
So far police haven't been able to identify the man who committed the robbery and threatened the staff at the bank.
Now they have released an E-fit picture of what they believe the man looks like based on descriptions of the witnesses during the incident.
Detective Constable Martyn Willis said: “This was a terrifying ordeal for the staff at the branch who believed the man had a firearm.
“Wed appeal to anyone who recognises the man to get in touch with us or Crimestoppers as a matter of urgency.”
Anyone with information regarding this incident should call police on 101 quoting 35/31345/18 or visit www.cambs.police.uk/report . Alternatively, contact Crimestoppers, anonymously, on 0800 555111 or via www.crimestoppers-uk.org .