Police have arrested a 36-year-old woman on suspicion of concealing a birth after the remains of a baby were found on a common in Tooting, south London.
The legs of a baby were found on September 10 at a council depot on Tooting Bec Common.
Experts determined that the infant was white, had been born two weeks ago and had gone to full term, though they could not say whether the baby was stillborn.
A woman was arrested on Monday in connection with the discovery, after members of the public said she was pregnant and approaching her due date at the time of the grim discovery.
The 36-year-old has been detained under the Mental Health Act, Scotland Yard said.
Detective Chief Inspector Mark Dunne said: 'She is somebody who we believe may have given birth and at this stage we can't locate that baby, so we needed to ask her about her baby.'
DNA tests are now under way to find out if the woman is any relation to the child.
Detectives contacted medical centres and schools in an attempt to trace the baby's parents, with DCI Dunne saying at the time: 'The focus right now is to identify the parents, particularly the mother because she or they are almost certainly going to be in need of some of the care services support.'