An inquest into the deaths of a cabbie who shot himself and three members of his family has heard there was no formal training for police officers involved in granting firearms licences.
Michael Atherton shot Susan McGoldrick, her sister Alison and niece Tanya, before killing himself last year.
The inquest also heard that one investigating officer at Durham Constabulary had never seen guidance by the Home Office or the Association of Chief Police Officers on issuing gun certificates.
Atherton legally owned six weapons, including three shotguns, despite having a history of domestic abuse.
Officers from Durham Police who gave evidence at Coroner's Office, Crook, County Durham, said there was no formal policy written down regarding firearms for them to use.
This led coroner Andrew Tweddle to describe the force's procedures as "more of an ad hoc arrangement".
The coroner has ruled that the deaths of three members of the same family, and their shooter, could have been avoided.
An inquest has heard how a man who went on to kill three members of his family before turning the gun on himself had been warned by police.
The inquest into the deaths of a man who shot himself and three members of his family on New Years Day 2012 has been taking place today.