Bodies found in a Carshalton house on Saturday had been there so long pathologists have not been able to identify them or how they died.
The bodies of a man and a woman were found in a semi-detached house in Mill Lane on Saturday afternoon after a neighbour became concerned at a lack of activity there for some time.
Police removed the bodies and post mortem examinations were carried out yesterday but the bodies were so decomposed the results were inconclusive in terms of both how the pair died and who they are.
A police spokesman said it is not yet known exactly how long the bodies have been there.
Neighbours told the Sutton Guardian the pair "kept themselves to themselves" and had not been seen for several weeks, but that this was not unusual.
Police said there is no evidence of any third party involvements and they are not suspicious about the deaths at this stage but the deaths remain unexplained.
Further tests on the bodies are set to be carried out over the coming days.