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Detectives have revealed the body of the Polish man dumped in a well in Warlingham was found just yards from where he once lived.
The dead man has been been named as Damian Chlywka, 32, who came to the UK in 2008. Detectives believe his body had been in the well in Audley Drive for around two years.
Police have made two further arrests. Two men, aged 41 and 33, have been questioned about the murder and released on bail.
Workmen discovered Mr Chlywka's body in a well outside an address in Audley Drive, Warlingham on 15 November. Met Police divers recovered the body but a post-mortem examination carried out two days later failed to provide a cause of death. Further tests are being conducted.
Detective Chief Inspector Cliff Lyons, who leads the investigation, said: "Damian had lived at various addresses across London including two known to be in the Croydon area. At one point he had lived at 11A Audley Drive.
"Our focus now is to build up a fuller picture of Damian's life in the UK. We have given the difficult and heartbreaking news to his family who are distraught that this has happened to their loved one.
"I am appealing to anyone who knew or previously worked with him to contact the police and help us to piece together a picture of Damian's life and how it came to end in these distressing circumstances."
Any witnesses or anyone with any information is asked to call the incident room on 020 8721 4961 or call Crimestoppers anonymously on 0800 555 111.
Officers initially arrested seven men, aged between 21 and 27, on suspicion of murder - they were interviewed and subsequently released on bail until a date in late December.