The death of a 16-month-old girl is now being treated as a murder investigation, police have said.
The toddler, from east London, died on September 17 from head injuries, according to a post-mortem at Great Ormond Street Hospital.
The youngster, who is not being named at this time, was taken to hospital after falling ill on September 13.
The Metropolitan Police arrested a 36-year-old man on suspicion of grievous bodily harm on September 14.
He has been released on bail until mid-October.
A force statement said: “The infant, from the E13 area, was admitted to an east London hospital after falling ill on Friday, 13 September.
“She died in hospital on Tuesday, 17 September. Officers know the identity of the child and next of kin have been informed. She is not being named at this stage.
“A post-mortem examination held on Monday, 23 September at Great Ormond Street Hospital gave cause of death as a head injury, pending further tests.
“A 36-year-old man was arrested on Saturday, 14 September on suspicion of causing grievous bodily harm. He has been released on bail to return in mid-October. Enquiries continue.”