'Mistakes will not reoccur'
The force is carrying out an internal review into why it took seven years to convict Anita's husband Alan Stead after he locked her in their garage and started a fire.
Stead was last week sentenced to a minimum of 25 years in prison after a jury found him guilty of murder.
Detective Chief Superintendent Joe Costello said: "We very much regret that the initial investigation was not as thorough or detailed as it should have been.
"The force is now structured differently to how it was at the time of Mrs Stead's death, with a major investigations department and our protective services division.
"We have stringent checks and processes in place to ensure that our initial responses to potentially major investigations are as rigorous and robust as possible.
"We will be conducting a detailed review of the case, with a view to identifying what went wrong. Some changes to our procedures have already taken place, but it is important that we learn from this as an organisation.
"We have liaised closely throughout the course of the investigation with Mrs Stead's family, who have had an unnecessarily long wait for justice."
ERRORS: Alan Stead murdered his wife Anita.

