Detectives investigating the discovery of a woman's body in a university lake have released a photograph of a dress she was wearing.
Officers have not been able to identify the woman since her body was recovered from the beauty spot at the University of East Anglia (UEA) on Thursday.
They have launched a nationwide search after ruling out the possibility that she was a student or member of staff at the university and say there are no links to any missing people inquiries in Norfolk, Suffolk or Cambridgeshire.
The dress is black with a large peach or cream rose pattern and a slightly gathered neckline and hem. It is size 10 and has ties on the shoulders but has no labels indicating where it was bought.
Do you recognise this dress?
Detective Inspector Richard Graveling, from Norwich CID said: "This is a fairly distinctive dress and we're keen to hear from anyone who may have seen a woman matching the description and wearing this item in the area around the university in the early part of last week.
"We are unable to establish where the dress was purchased and would be keen to hear from any retailers who believe they stock the item."
The woman, who was spotted floating face down in the water by an angler, was 5ft 7ins, slim and in her late 30s or early 40s. She had short dark brown hair with a natural wave, which had been dyed auburn or dark red.
A post-mortem examination has so far failed to establish the cause of death and further tests are being carried out.
Mr Graveling said: "There is no evidence at this stage to suggest the woman was the victim of violence or that a third party was involved, however we are keeping an open mind as to the circumstances surrounding the discovery."
Anyone with information should contact Norwich CID on 101.