The actions of Michael Atherton on New Year's Day 2012 would see four dead. He'd shoot his partner Susan McGoldrick, as well as Susan's sister and niece Alison and Tanya Turnbull. He then killed himself.
At the end of the inquest into their deaths the coroner, Andrew Tweddle, said had gun licensing procedures at Durham Police been more "robust", the victims' death could have been avoided.
Atherton owned six weapons including three shotguns, despite having a history of domestic violence towards Susan, as well as alcohol problems.
He also threatened to shoot himself in 2008 and his guns were taken off him. But they were later given back to Atherton with a warning letter.
Mr Tweddle said he will write to the Home Office calling for "root and branch" changes to gun licensing, saying it was "fortuitous" there had not been more incidents like the one in Horden, near Peterlee on New Year's Day 2012.
He added it was difficult to concede an area of the law where an urgent review is so essential.
Bobby Turnbull told ITV News in a question and answer session after today's inquest that the apology from Durham Constabulary does not mean a lot to the family.
Durham Constabulary have faced questions over their handling of granting firearms licenses in the wake of the Horden shootings.