Police were called to Rawnsley Avenue after human remains were found in a river by contractors carrying out cleaning work.
Officers attended and a crime scene was established.
Following examination of the remains, detectives informed the family of Sarah of this development.
Sarah was 38 and was from Croydon and her partial remains were found in Rowdown Fields in New Addington on April the 2nd. This is when Police opened their investigation into her murder.
Detective Inspector Martin Thorpe, who is leading the investigation, said: “My thoughts remain with Sarah’s family.
“We will continue to provide our support as our investigation progresses.
“Two people arrested, who were known to Sarah, were later charged with her murder. At present we are not looking for anyone else in connection with her death. Enquiries are ongoing.”
Anyone with information that may assist the investigation who has yet to speak with police is asked to call 101, quoting reference 1656/02Apr.