A thief stole a woman's handbag from the St Helena Hospice Shop in Head Street.
They struck as the 40-year-old victim was talking to staff in the store at about 12.45pm on Thursday.
The bag is described as a brown leather clutch bag with silver zip. Items inside the bag were a HTC mobile phone, passport, £40 cash and credit card. There is no description of any suspects.
Investigating officer Pc Wicks said: "The victim is really upset about this and would like to appeal to the person that took it to return the items."
Anyone with information is asked to call Pc Wicks at the Neighbourhood Crime team at Colchester on 101.