Hundreds of officers have been desperately searching for the infant in the Brighton and Newhaven areas.
Constance Marten and Mark Gordon have been further arrested on suspicion of gross negligence manslaughter.
Police originally arrested the couple on suspicion of child neglect on Monday, February 27th.
The couple was arrested after a member of the public spotted the pair in Brighton yesterday.
However, their baby was not with them. They have refused to tell police where the infant is.
Hundreds of officers have been desperately searching for the infant in the Brighton and Newhaven areas.
Met Police Detective Superintendent Lewis Basford issued an update this afternoon.
He told reporters that the couple has told police nothing about their baby.
https://twitter.com/sussex_police/status/1630539150838341633
They don't know where the child is. They also don't know the child's gender or if it has any health issues.
He told
Sky News;
"We now have to consider the possibility that the baby has come to harm."
"Clearly the risk is getting higher... this may not end in the way we would like, but we need to remain hopeful."
Officers are hoping to find the baby alive, but the cold weather is a major concern.
The baby also hasn't had any medical treatment since it was born in January.
Following their arrests on Monday, police issued a
statement;
"Shortly before 21:30hrs on Monday, 27 February, a member of the public reported a sighting of Constance Marten and Mark Gordon in Stanmer Villas, Brighton."
The pair remain in police custody.
Searches for the infant continue.
"The baby is still missing and an urgent search operation is taking place in the area.
Police launched an investigation into Gorden and Marten's disappearance on January 5th.
