The remains were discovered during a search for the two-month-old baby of Constance Martin and Mark Gordon, police said.
After evading police for more than seven weeks, Sussex Police located Martin and her partner Gordon, who did not have their children, at Stammer House in Brighton on Monday night.
Det Supt Lewis Basford of the Metropolitan Police said the remains were found in a wooded area on Wednesday.
The couple refused to tell police where the baby was, sparking a massive search across a vast area of rural Sussex.
More than 200 officers and specialist search teams scoured the area around Stanmer Villas before eventually finding the couple following a tip from a member of the public. They were arrested on suspicion of child neglect and later on suspicion of gross manslaughter.
An abandoned sleeping bag, tent and several rough camps and shelters have been found in woods near an area where police in Brighton were searching for signs of the missing baby of arrested couple Constance Martin and Mark Gordon.
The discovery was made in a forested belt bordering the southeast corner of the wild park – an area it is understood has not been searched by police. The woodland is in a 240-acre reserve on a direct off-road walking route between Newhaven and Fiveways and the couple were arrested in Brighton on Monday night.
Police were notified of the discovery.
Meanwhile, police continue to search for the runaway couple’s children and have requested an additional 36 hours to question them. The discovery was made in the forest belt that now borders the southeastern corner of the wild park
An abandoned sleeping bag, tent and several rough camps and shelters were found today
The Metropolitan Police, which led the search in Brighton along with hundreds of officers, said again today that they “must bear in mind that the baby suffered serious injuries”. The size of the area searched indicated that neither Maarten, 35, nor Gordon, 48, disclosed the whereabouts of the newborn who was questioned.
Detective Superintendent Lewis Basford said: “This has been an extremely difficult and exhaustive search operation covering a vast area of approximately 90 square miles. We are using every resource we have to find the baby.”
He called on the public to remain vigilant and continue to provide police with information. The baby was never photographed, but two taxi drivers who took the couple on the ferry in early January said they could see the baby moving and heard him cry during the journey.
They were seen looking “dodgy” on a board near Brighton a week ago as they picked up supplies without their children. The size of the area searched indicated that neither Maarten, 35, nor Gordon, 48, had disclosed the whereabouts of the newborn, who was questioned after his arrest on Monday