A police officer involved in the initial investigation into the death of Poppi Worthington has been demoted.
Poppi was 13 months old when she was found with serious injuries at her home in Barrow, Cumbria, in December 2012.
Cumbria Police has now concluded performance proceedings into the competence of an officer involved in the initial investigation.
The BBC understands Det Insp Amanda Sadler admitted gross incompetence and was demoted to the rank of sergeant.
Following Poppi's death a family judge ruled that, on the balance of probabilities, she had been sexually assaulted by her father, Paul Worthington.
He was questioned on suspicion of sexual assault but never charged with any offence. He denies any wrongdoing.
In September, the Crown Prosecution Service announced it was carrying out a fresh review into the death.
Cumbria Police said performance proceedings were held in front of a panel, which was chaired by an independent senior officer from outside the force.
The officer admitted their actions in relation to the initial investigation into the death of Poppi amounted to gross incompetence.
The panel determined an immediate reduction in rank and the force will now consider the role the officer will undertake.
It said in a statement: "We are unable to comment any further on these proceedings."
Barrow and Furness MP John Woodcock said: "The public will find it difficult to understand why one of the key officers responsible for this investigation retains a senior position in the force despite admitting to gross incompetence in this highly sensitive case.
"The force should not be allowed to scapegoat one officer when it is clear there was manifest incompetence and systemic failing at all levels of the force that need to be acknowledged and acted up if we are to restore confidence in the police in Cumbria."