Braintree detectives are appealing for information after a robbery at the Church Street Co-Op store yesterday afternoon.
At about 4pm, a man walked into the Bocking shop with a knife.
He threatened a member of staff and made off with a quantity of cigarettes.
He left the shop on foot. No one was injured.
The police helicopter was used to search for the suspect but he was not found.
Dc Andy Young, the officer investigating, said: "We would like to hear from anyone who may have seen a suspicious man loitering near the Co-Op between 3.30pm and 4.30pm on Tuesday, April 22.
"He is described as being mixed race, possibly in his mid 20s, of medium build and was wearing a dark coloured hooded top with the hood up, grey jogging bottoms and pink sunglasses.”
Anybody that can help with information about his incident is asked to contact Dc Andy Young at Braintree on Essex Police 101 or Crimestoppers anonymously on 0800 555 111.