Plymouth gunman Jake Davison had an argument with his mother before shooting her in the head at the start of his attack, an inquest has heard.
The inquest into the deaths of Davison‘s victims has now formally opened, with police providing evidence about the circumstances of the killings.
All five victims died from shotgun wounds, the court was told.
Police are not looking for any other people in connection with their deaths.
The results of toxicology tests, which look for traces of drugs in the victims’ bodies, and histology tests, which involve the examination of sampled whole tissues under a microscope, are still pending.
Maxine Davison, a former trawler, died at her home in Biddick Drive, in the Keyham area of Plymouth.
“The circumstances of her death are that Maxine sustained fatal gunshot wounds following an argument with her son,” Detective Steve Hambly, the senior investigating officer, said.
He said the medical cause of her death, based on current evidence, was shotgun wounds to her head and torso.
The other four victims did not know Davison, the inquest was told.
Davison’s subsequent victims, three-year-old Sophie Martyn and her father Lee, 43, were walking their dog in Biddick Drive when they were killed.
They were both fatally shot in the head, while Mr Martyn also sustained shotgun wounds to his chest.
The gunman went on to enter a nearby park, where he killed Stephen Washington, 59, who was walking his dogs.
Mr Washington, who was a carer for his wife, died from gunshot wounds to his chest.
The final victim of Davison’s rampage was Kate Shepherd, a 66-year-old married artist, who was fatally shot in the abdomen on Henderson Close. She later died in Derriford Hospital.
In a separate five-minute hearing, the coroner opened and adjourned the inquest into the death of Davison, who died after shooting himself in the head before police could reach him.
The coroner adjourned all inquests and scheduled another hearing on 9 December.