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 today.
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.
The spokesperson added: "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."
It was following that arrest that police seized his firearms for a number of weeks before returning them when he applied to have them back.
Assistant Chief Constable Michael Banks said: "As many people know, Mr Atherton and Ms McGoldrick had what might be described as a volatile relationship.
"However, I am satisfied that these incidents were dealt with appropriately at the time and apart from the incident referred to in 2008 police have not been called to the family home for more than seven years.
"There may well have been other incidents in those intervening years, however if they were, the police were not informed."
The Independent Police Complaints Commission is examining Durham Police's handling of how Atherton's firearms were licensed.
Meanwhile, 19-year-old Laura McGoldrick, who escaped through a window as her mother was shot dead, said she would see her in heaven.
She was hit by the spray of shot fired at her 47-year-old mother but was not badly injured.
Yesterday, after inquests were opened briefly, Detective Superintendent Paul Goundry said officers had spoken to Atherton's GP and other health professionals and there was no indication he was suffering from any mental illness.
Atherton carried out the killings with a shotgun - one of several firearms held legally - which is now being examined by ballistics experts.
Detectives believe the shootings were not pre-planned and were sparked by a "relatively trivial family argument".