Police say it has been seven weeks since 96-year-old Nellie Herriott was reported missing from her Brighton home and they are now scaling their search down.
The search for the very independent pensioner involved police investigating over 70 reported sightings, using specialist search teams, viewing many hours of CCTV, regularly checking local hospitals and a high profile social media campaign in a bid to locate her.
Det Insp Miles Ockwell, who led the investigation said: "It is very sad that despite an intensive investigation combined with tremendous help and support from the public and media, Nellie is still missing.
Our thoughts are very much with her family and friends who still do not know what has happened to her.
"The case will not be closed down completely - I will personally review it on a monthly basis for the first three months and then six monthly after that and any new lines of inquiry that come up in the meantime will be investigated."
Nellie's niece, Lesley Hogg said: "I'd like to thank Sussex Police, social services and the public, especially in Brighton, for their amazing help and genuine participation in trying to find Nellie - which we have found very heart warming.
"It has all been very distressing, terrible and unfortunate. Nellie has always been an independent lady who loved her freedom. It is so sad that she has not been found."