Police were called to the home of Peterlee shotgun killer Michael Atherton four times in just two years over domestic violence incidents, a spokesman said.
The taxi driver murdered his partner Susan McGoldrick, her sister Alison Turnbull and her niece Tanya Turnbull before turning his shotgun on himself on New Year's Eve.
Durham Police said the couple who lived in Horden, Peterlee, had "a volatile relationship".
A police spokesman said: "After studying records going back a number of years, police today confirmed that between 2002 and 2004 police were called to a total of four domestic-related incidents at the house, none of which resulted in either party being charged with any offence.
"Two of the incidents resulted in an arrest; the first was in July 2002 when Mr Atherton was arrested to prevent a breach of the peace following an argument between him and Ms McGoldrick.
"And in April 2004 he also received a police caution for common assault on Ms McGoldrick after he returned home in an intoxicated state. Since then the only time police have been called to the home was the incident in September 2008 when Mr Atherton was alleged to have threatened to shoot himself.
"He denied this and after initially being arrested to prevent a breach of the peace he was released."
Laura McGoldrick, 19, who escaped through a window as her mother was shot dead, said: "As you can imagine, this week has been extremely traumatic and upsetting.
"Not only have I have suffered the loss of my fantastic mam and a lovely auntie and cousin, I have been involved in a very frightening situation.
"I would like to say a few words about my mam and what she meant to me. To my beautiful and gorgeous mam, I love you with everything I have got. Words cannot describe how much I miss you. See you in heaven."