A man has been arrested and released on bail over the death of a 10-week-old baby girl from Loughborough.
Baby Lila was admitted to hospital with "serious injuries"
Lila Robertson was admitted to the Leicester Royal Infirmary on Sunday, suffering from serious injuries but died on Tuesday evening.
A 28-year-old man was arrested on Sunday on suspicion of causing grievous bodily harm but was released pending further inquiries, police said.
Lila's mother, who does not want to be identified, said she was devastated.
"I am finding it hard to come to terms with the loss. This is a particularly difficult time for me and I ask that the media respect my privacy and allow me to grieve in peace," she said.
Det Supt Chris Thomas, from Leicestershire Police, said a post-mortem examination had been inconclusive and further tests were being carried out.