The brother of a woman who was shot dead along with her son by her estranged husband has welcomed news of a Commons debate on the matter.
Alan Pemberton was accused of abusing his wife
Frank Mullane's sister Julia Pemberton was shot, along with her son William, by Alan Pemberton in Newbury in 2003.
Mr Mullane of Swindon has already called for an inquiry into the deaths.
He hopes the fact that his MP, Julia Drown, plans to raise the matter in Parliament on Wednesday will lead to improvements in police practice.
Mrs Pemberton had told officers she was being abused and threatened by her husband before he shot them at their home.
She was advised to have a panic alarm installed, but it was never used.
At the inquest, police said she had not made a formal complaint and in such cases their role was advisory - it was up to individuals to decide what action to take.
East Berkshire coroner Peter Bedford recorded verdicts of unlawful killing on Julia and William Pemberton.
He said police could not have prevented their deaths.