The coroner overseeing the case of the Plymouth gunman, Jake Davison, who killed his mother and four other people, has asked a watchdog to examine whether changes to weapons licensing have been made since a man shot dead three women in the north of England almost 10 years ago.

At the opening of inquests into the deaths of Jake Davison and his five victims, it emerged that the 22-year-old apprentice crane driver shot his mother in the head and torso after an argument. He went on to kill four people he did not know, including a three-year-old girl, in nearby streets and a park. He then shot himself in the head, the court was told.

The Independent Office for Police Conduct (IOPC) is investigating why Davison was given a shotgun certificate despite his history of mental health issues, and why his licence was returned to him last month after being confiscated because of an allegation of assault.

The senior coroner in Plymouth, Ian Arrow, asked the IOPC to examine the case of Michael Atherton, 42, who killed his 47-year-old partner, Susan McGoldrick, her sister Alison Turnbull, 44, and her niece Tanya Turnbull, 24, before taking his own life on New Year’s Day 2012. The four bodies were found in Horden, near Peterlee, County Durham.

An inquest in 2013 found that despite a history of domestic abuse and threats to self-harm, Atherton legally owned six weapons, including three shotguns, and the coroner, Andrew Tweddle, said he would write to the Home Office calling for a “root and branch” review of British gun licensing.

Arrow called for the IOPC to consider any changes made by the Home Office or by chief police officers since the Atherton tragedy.

The coroner was told that Davison’s mother, Maxine, 51, a former trawler worker, died at her home on Biddick Drive, Keyham, last Thursday after a row with her son.

Lee Martyn, 43, a carpet fitter who was walking the family dog with his daughter Sophie Martyn, died on Biddick Drive after Davison walked out of his mother’s house and turned his weapon on them. Father and daughter sustained gunshot wounds to the head, with Lee Martyn also shot in the torso.

Stephen Washington, 59, a carer for his wife, was shot in the chest as he walked his dogs on “Snakey path” in a park that adjoins Biddick Drive.

Kate Shepherd, 66, a married artist, was shot in the abdomen on nearby Henderson Place. She received immediate medical attention, the court heard, and was taken to hospital but could not be saved.

DI Steve Hambly, who is leading the investigation into the shootings, codenamed Operation Lily Pad, said that apart from Davison’s mother, the victims had been attacked by a person not known to them.

Hambly, a member of Devon and Cornwall’s major crime investigation team, gave brief details about each victim during a 10-minute hearing. He said Maxine Davison was born in Plymouth and had worked on trawlers, though not for a number of years. “She sustained fatal gunshot wounds after an argument with her son,” said Hambly.

Lee and Sophie Martyn were walking the family dog on Biddick Drive. Hambly said they were shot by an “assailant” not known to them. Both father and daughter were born in Plymouth; Sophie on Christmas Eve 2017.

Hambly said Washington was born in Surrey but lived in Plymouth, while Shepherd was born in Woolwich, south-east London, and also lived in the Devon city.

At a second brief hearing focusing on the gunman, the court was told he was born in Plymouth and died on Henderson Place when he took his own life, sustaining shotgun wounds to the head.

No possible motive was discussed but Davison’s social media has suggested a strong interest in the “incel” – or involuntary celibate – movement, as well as a deep interest in guns.