The brother of a woman who was shot dead along with her son by her estranged husband has criticised the police response to the tragedy.
Alan Pemberton was accused of abusing his wife
East Berkshire coroner Peter Bedford recorded verdicts of unlawful killing on Julia and William Pemberton who were gunned down at their Berkshire home.
He said police could not have prevented their deaths.
But after Wednesday's verdict, Frank Mullane condemned the six-hour delay before officers entered the house.
The hearing was told Alan Pemberton, 48, killed his wife and 16-year-old son, before turning the gun on himself.
Earlier, the coroner was told Mrs Pemberton pleaded with a police operator that she had "about one minute before I die" as she hid in a downstairs cupboard while her husband rampaged through their home in Hermitage, Berkshire.
However, despite receiving the call at 7.11pm, police did not enter the property until 1.53am the following day.
Mr Mullane called for the police response to firearm incidents to be looked at.
He also said his sister should have had more protection from her husband.
But Thames Valley Police superintendent Jim Trotman said: "I am confident that Thames Valley Police offered Julia Pemberton advice and support which we felt was appropriate at the time.
"Since the incident the force has doubled the number of armed response vehicles it has in an effort to improve our response to live firearms incidents of this kind."
Earlier, recording his verdict, Mr Bedford said that in his opinion, the deaths were inevitable.
"Nothing could have prevented him (Mr Pemberton) doing what he did," the coroner said.
"That will come as no solace to the family.
"The only way Julia Pemberton's life could have been saved is if she had had an armed escort throughout the 15 months before she died."
Describing Mr Pemberton as "a man with a plan", the coroner added: "William, I suspect, did the wrong thing or got in the way and paid the ultimate price.
"It is difficult to fathom what Will could have done to justify such behaviour from his father."
Mr Pemberton was a callous and desperate man, the coroner said, who could not come to terms with the loss of "his wife, his business and his house".
Family friend John Cownley told Wednesday's hearing Mr Pemberton was "stressed" by claims he abused his wife.
Detective Inspector Steven Reschwamm, the investigating officer, told the hearing that Mr Pemberton had left a note which read: "I have paid a substantial amount of cash to have her (Julia) killed if I fail myself."
"I hated to think that I died with my children thinking I had raped their mother," he wrote.
"My anger for what she has done and the callous way in which she has done it left me with no alternative but to take my revenge."
The couple's surviving daughter, Laura Pemberton, 20, who was away at university at the time of the shootings, read a statement at the end of the inquest.
She said: "As you can imagine, it has been a very difficult time for me since the tragic loss of my family last November.
"Now that the inquest is over I would like to try to get on with my life.
"I am very grateful to everyone who has supported me through the past months, especially my family and friends."