An inquest into the death of a taxi driver who shot three members of the same family before turning the gun on himself is taking place.
Michael Atherton, killed his partner Susan McGoldrick, her sister Alison and niece Tanya, before taking his own life on New Year's Day 2012 at his home in Horden.
Atherton legally owned firearms despite a history of domestic violence.
He had his guns removed by police after he threatened to blow his own head off when drunk, but they were returned weeks later.
Alison Turnbull's son Bobby wants to tighten gun ownership legislation to stop further tragedies.
He has already won the backing of shadow home secretary Yvette Cooper after meeting her earlier this year.
Bobby is calling for changes to gun laws, including stricter checks of medical records, and hopes the coroner will make recommendations to the Home Secretary at the end of the hearing.
– Bobby Turnbull - victims' son, brother and nephew
"There's a lot of little questions I have that I want answering.
"I hope they will come out through the course of the inquest, which might put my mind at rest and help me to understand."