Police in the UK investigating the case of Constance Marten and Mark Gordon believe the remains of a baby found in woodland in Brighton “may have been dead for some time”.
Officers have also been unable to confirm the infant’s gender and a post-mortem has not yet taken place.
It is “too early” to provide a specific date of death, the Metropolitan Police said.
Speaking at a press conference on Thursday, Detective Superintendent Lewis Basford also said the case has been referred to the police watchdog.
He said: “At this stage we have not yet been able to confirm the baby’s gender and post-mortem examination has not yet taken place.
“Despite this, based on our inquiries we’ve carried out so far, we believe sadly the baby may have been dead for some time before they were found.
“It is too early for us to provide a more specific date.
“Because we believe the death occurred during the course of a missing person investigation we have made a mandatory referral to the Independent Office for Police Conduct (IOPC). This is standard protocol for such circumstances.”