A dad-of-two who annihilated his own family before taking his own life participated in a family FaceTime before the slaughter, an inquest heard.
Robert Needham, 42, used a legally-obtained shotgun to kill daughters, Ava, four, Lexi, two, wife Kelly Fitzgibbons, 40, and the family dog Billy before turning it on himself.
Today, coroner Bridget Dolan QC apologised to the families saying she was sorry the inquest had not answered the single biggest question of why Needham carried out such an act.
She also praised Kelly's family, who attended the inquest, and said: "I'm so sorry this inquest has not been able to answer why this atrocity happened."
Ms Dolan said it was clear Needham had killed his family and then himself at the converted farm building in rural West Sussex they shared with his mother in March 2020.
The inquest heard that the family were last seen by a delivery driver who brought takeaway food on the first Saturday night of lockdown.
The builder also took part in a family FaceTime call and nothing was out of the ordinary, the inquest heard.
That night the girls got into their parents' bed and that is where their bodies were found the next day.
The coroner said it was impossible to know the timing or order in which they were killed, only that Needham was last.
They were all shot from close range or with the muzzle of the gun in direct contact, Ms Dolan said.
She said: "Having brutally murdered his family, Robert took his own life.
"The outstanding question is why these dreadful events happened. There's an awful lot to speculate on but very little evidence
"I'm very sorry for you there is no explanation. Everybody who investigated this tried to find one for you.
"We just cannot take this point any further. His own family said there was no plausible explanation for his diabolical actions and I agree with that."
Kelly and Needham were described as a loving couple who had been together for 14 years.
They had some personal debts but nothing unmanageable, the coroner said.
Text messages in the two months leading up to lockdown showed there were tensions in their relationship with Kelly raising the possibility they should take a break.
"However, there were no threats, no swearing, no sustained or lengthy argument," the coroner said.
His history of cocaine abuse was unlikely to have been a factor, the coroner concluded.
Needham had been treated for depression although he had never been referred to a psychiatrist, the coroner said.
Hampshire and Sussex Police had shown a lack of investigative curiosity when considering Robert Needham's applications for a shotgun and firearms licence.
The coroner said that even though there are significant questions about the licensing procedure, further scrutiny of his applications would not have led to rejections.
He had lied on the application forms and the police should have investigated further.
The false statements were important but would not have led to his application being refused, the coroner said.
Emotional descriptions of both girls and their mother were read by the coroner.
Emma, Kelly's twin sister, read part of her eulogy for the inquest. She said: "People couldn't tell us apart.
"Kelly loved school and, although not sporty, we could never be beaten in a three-legged race.
"She was an amazing sister and we were fiercely loyal to each other. No one made me laugh more."
She continued: "Everybody would comment on her smile kindness and her funny and caring nature. She was warm and loving and people naturally warmed to her."
Emma described the loss of her sister and nieces to the family as incomprehensible.
She said: "Ava was a beautiful, angelic little girl. She was a chatterbox with inner strength when she wanted it."
Lexi had cheekiness all over her, her aunt said.
She added: "Such a character, she greeted every day with energy and enthusiasm.
"We will never understand what happened and we will always feel blessed to have had them in our lives."