The family of a woman and her son shot dead by her estranged husband have won a review into police actions leading up to the killings.
Mrs Pemberton's family say there were earlier warning signs
The deaths of Julia and William Pemberton, who were killed at their Berkshire home in 2003, are to be the subject of a formal review.
Mrs Pemberton's brother Frank Mullane, from Swindon, Wiltshire, has been campaigning for the review.
He believes Thames Valley Police failed to take steps to prevent the killings.
The murders, at the hands of William's father, Alan, came after a series of incidents which family members believe should have been recognised as clear alarm bells.
At the time of the tragedy, Mr Pemberton was already the subject of a court order banning him from going anywhere near the family home in Hermitage, near Newbury.
Last month, Mr Mullane was accompanied by his niece, Laura, to meet Home Office minister Baroness Scotland to call for a formal homicide review into the tragedy.
In discussions held with the minister as a result of the family's meeting, Thames Valley Police Chief Constable Peter Neyroud agreed to the review process taking place.
The full scope of the procedure, which is expected to bring together all the relevant agencies which dealt with the case, has yet to be agreed.
The case would be one of the first to be examined under the homicide review procedure introduced under the Domestic Violence Crime and Victims Act 2004.
A spokesman for the force said: "The chief constable of Thames Valley Police has confirmed his willingness to hold a review with regard to the Pemberton case and will be meeting Home Office representatives in the near future to discuss this."
In a statement issued through the Catholic diocese of Portsmouth, the family welcomed the decision.
The statement said: "We will keep pushing so that this review has to address the numerous system failures of Thames Valley Police during this tragedy.
"Our aim is to ensure that Thames Valley Police learns the lessons and implements an appropriate and positive policy in their handling of domestic violence situations in the future and its firearms policy is fundamentally reviewed and changed."
"We believe that if Thames Valley Police had responded appropriately and professionally to this case of domestic violence, this tragedy could have been avoided.
"We do not want any other family to have to go through what we have experienced."