A coroner will write to prosecutors with her outcome following an inquest into the death of a baby girl in July 2010.
Nina Fretwell died from a fatal head injury at her home on Station Road, where she lived with parents Yunmei Xie and Paul Fretwell, now separated.
At Derby Coroner’s Court, Deputy Coroner Louise Pinder recorded an open verdict into her death which occurred while in the care of her father.
Mr Fretwell, who was arrested shortly after the incident but released due to lack of evidence, alleged that Nina fell down five stairs that led down from the flat while he was collecting bags of shopping. However, experts said such a short fall would be unlikely to kill a child and noted a large number of bruises on Nina’s body, sustained before the incident.
Ms Pinder concluded that the head injury which killed Nina not could not have happened the way Mr Fretwell described.
She said: “The precise circumstances of how Nina Fretwell sustained a fatal head injury while in the care of her father remains unexplained,”
A spokesman for Derby Coroner’s Court confirmed that Ms Pinder would write to the Crown Prosecution Service to inform them of the outcome.
Derbyshire Police said a full investigation was initially carried out and a file presented to the CPS, but there was insignificant evidence to charge anyone.