Teams from mountain rescue organizations have joined the search for Constance Marten and Mark Gordon‘s infant.
On Monday night, the pair was taken into custody in Brighton.
After over two months on the run, they were apprehended on accusations of child maltreatment and are still being held in police custody.
Teams are frantically searching a sizable area between Brighton and Newhaven in an effort to locate the baby, who has been missing since his birth in early January and has not received any medical care.
This morning, officers from London Search and Rescue could be seen in orange hi-vis jackets searching Moulsecoomb Wild Park.
The wooded nature reserve is around a mile from where Marten and Gordon were arrested.
Officers, some wearing jackets indicating they were dog handlers, searched underneath sticks and logs close to where the area meets Hollingbury Golf Course.
At the start of each section of their searches, one shouted: ‘Are we ready? Look behind you, and let’s get going’ before they walked in a line, scouring the area.
A uniformed officer was seen standing guard at the entrance to the park, with dog walkers saying they saw police tape cordoning off parts of the woodland.
In a press conference yesterday, police said they still ‘hold hope’ that the missing baby is still alive, but have warned ‘risk to the child is extremely high’.
A Met Police spokesperson said: ‘Whilst we hold hope that the baby is still alive, we agree that the risk to the baby is extremely high.
‘More than 200 officers have been engaged in the search and officers arrived within 6 minutes after the 999 call yesterday that led to the arrests of Constance Marten and Mark Gordon.’
Police have also searched every shed at the Roedale Valley Allotments near where Marten and Gordon were arrested and will remain on site for some time.
An entry on the allotments society Facebook page said officers had forced entry to outbuildings as the hunt for the two-month-old baby continues.
The couple had avoided police since the infant was born in early January.
They moved around the country, paying for everything in cash and covering their faces when on CCTV.
But a tip-off led to them being detained at around 9.30pm on Monday by officers from Sussex Police in Stanmer Villas.
CCTV footage had showed Marten and Gordon walking past a row of houses in Brighton, both with their hoods up, prior to their arrest.
A neighbour told The Sun the ‘suspicious’ couple walked by her house at 8.40pm with no shopping bags, then returned at 9.25pm carrying two bags of food from a shop.
Walking behind Marten, Gordon can be seen carrying what appears to be a large metal pipe, and can be heard ‘shouting’ at her.