A date has been set for a review into how a man who was banned from going near his family home was able to shoot dead his estranged wife and their son.
Mrs Pemberton's family say there were earlier warning signs
The group will examine the murders of Julia and William Pemberton, 17, who were killed at their Berkshire home by Alan Pemberton, who then shot himself.
Mrs Pemberton's brother Frank Mullane, from Wiltshire, believes their deaths in 2003 could have been averted.
He says police did not heed the warning signs. The review begins on 1 October.
During a meeting on Monday to finalise the review's remit, Mr Mullane drew on the case of beauty consultant Clare Bernal, 22, who was shot dead at Harvey Nichols in Knightsbridge, London, by Michael Pech, 30, who had already pleaded guilty to harassing her a fortnight before.
He said: "It is imperative that all the agencies that come into contact with perpetrators and potential victims need to know the danger signs.
"If this review doesn't look at that, what's the point of it?
"It is a matter of risk assessment. All the agencies have to understand the high risk signs, so the review must make proposals as to how that information should be conveyed to the agencies."
Brian Parrott, former Surrey social services chief, will conduct the review.
It was commissioned by the West Berkshire Safer Communities Partnership, which includes police, the local authority and other groups.
The review - believed to the first of its type in the UK - is set to shape how investigations into similar tragedies will be carried out.
'High risk prioritised'
A Thames Valley Police spokesman said: "In the past year the force has made a number of improvements to the way in which it responds to firearms and domestic violence incidents.
"The force has developed a risk assessment process drawing on national guidance.
"This has been piloted in two police areas and will be rolled out across the whole of Thames Valley shortly.
"This will help officers to identify which victims are high risk and need to be prioritised. "