A man has been arrested on suspicion of murdering a one-year-old boy and attacking his twin sister
Bidhya Sagar Das, 33, lived at the address in Finsbury Park area in north London where the toddlers were attacked in what police are describing as a suspected "domestic incident".
Detectives confirmed "the man was at the flat shortly before the injured children were found, but left before emergency services were called."
"The incident is believed to be domestic and enquiries continue," it added
Horrified neighbours had reported a woman, believed to be the children's mother, rushing out of the home screaming, "My children, my children!" shortly after 11:00 pm on Saturday
The boy was pronounced dead before 1:00 am after both the children were taken to an east London hospital
Police said next of kin are aware and a post-mortem will be carried out on the little boy in due course
The little girl remains in a critical condition in hospital
Officers were seen going door-to-door on Sunday as police remained outside the three-storey building. Neighbours said officers had been searching properties along the tree-lined street
Eyewitness Mihai Manea told reporters at the scene: "We heard the noise and went to the room...the boy was already dead. (We are) just shocked, you wouldn't expect something like this...when I saw the police, I said, 'It's just Saturday night, it's like, somebody got drunk or in a fight but I wouldn't imagine like a murder."
The Metropolitan Police have not confirmed how the children were injured, but said a murder investigation has been launched by its Homicide and Major Crime Command.
Det Ch Insp Dave Whellams, who is leading the investigation, said: "This is clearly a tragic incident, and our thoughts are with the family of the two young children.
"Despite the best efforts of medical professionals, a baby boy sadly died in the early hours of this morning.
"A baby girl currently remains in a critical condition and is receiving specialist medical care.
"Whilst we remain in the early stages of the investigation, a man has now been arrested.
"I would still like to hear from anyone who may have any information regarding this terrible incident."
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