A one-year-old boy has died after being found injured at a north London flat.
Police called to Wilberforce Road in Finsbury Park on Saturday night also discovered a girl the same age, who is in a critical condition.
Both toddlers were taken to an east London hospital after the discovery at 23:10 GMT. The boy died in the early hours of Sunday.
A neighbour told the BBC that a woman came downstairs screaming for help, and another neighbour called the police.
Detectives said inquiries were under way to “establish the full circumstances”.
No arrests have been made, but the Metropolitan Police added: “Next of kin are aware.
“Formal identification awaits and a post-mortem examination will be scheduled in due course.”