Police have arrested a man on suspicion of the murder of a one-year-old boy and the attempted murder of a girl of the same age, thought to be his twin.
Bidhya Sagar Das, 33, who is believed to be the woman's partner, had been sought in connection with an incident at a flat in Finsbury Park, north London.
An emergency call was made from Wilberforce Road in the late hours of Saturday (18 March) and both children were rushed to a hospital in east London when officers and the London Ambulance Service (LAS) arrived at 11.10pm.
A Met Police statement said: "Next of kin are aware. Formal identification awaits and a post-mortem examination will be scheduled in due course. The girl remains in hospital in a critical condition."
The boy was pronounced dead at 12.48am on Sunday (19 March). Detective Chief Inspector Dave Whellams from the Metropolitan Police Homicide and Major Crime Command is now investigating the incident and has opened enquiries "to establish the full circumstances of the incident".
Detective Chief Inspector Dave Whellams from the Metropolitan Police Homicide and Major Crime Command is now investigating the incident and has opened enquiries "to establish the full circumstances of the incident".
The suspect worked at the nearby Pembury Hotel along with a neighbour Mihai Menea. Police have not released the cause of death of the boy. A neighbour calling herself "Gui Gui" said that a woman came downstairs from the flat screaming, prompting another neighbour to dial 999.
"I was watching TV. I heard someone was shouting. She kept on shouting. I do not know what she was shouting," she said. I opened the window and I asked her 'Can I help you, can I call the police for you?'
"She said, 'My kids, my kids.'"
Met Police declined to comment on reports the children were attacked with a hammer, when approached by IBTimes UK.
The National Police Air Service dispatched a helicopter to search the surrounding area and find any potential suspects involved.
Anyone with information that may assist the investigation is asked to contact the incident room on 020 8345 3775.