A murder investigation has been launched following the death of a girl, aged 16 months.
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.