Police have named the victims of a New Year's Day gun rampage in which a man shot himself after killing three women.
The bodies were found in "close proximity" downstairs in the semi-detached house in Greenside Avenue, Horden, Peterlee, after police were alerted to shots being fired shortly before 11.45pm on Sunday night.
Police believe family members had been out at a pub or for a meal before returning to the house where the incident took place.
As the shooting began, a teenager, understood to be Mrs McGoldrick's 19-year-old daughter Laura, fled through an upstairs window and raised the alarm. She ran into the street and pounded on a neighbour's front door asking for help.
Durham Police revealed that police had had "minor contact" with the family in the past. In 2008 police were contacted after claims Atherton was threatening to harm himself.
The matter has been voluntary referred to the Independent Police Complaints Commission (IPCC) by Durham Police, as the force had previous contact with the family.
A spokeswoman for Durham Police said last night: "Police are continuing to try and establish the exact circumstances of what took place and are speaking to family, friends and associates of those who died.
"However, we can confirm that police currently believe Mr Atherton shot the three women before turning the weapon on himself.
"The exact weapon used has still not been established and will also form part of continuing inquiries."
Post-mortem examinations were being carried out last night, and police hoped to release more details today.
The families of those involved have asked not to be contacted by the media. Some of the victims' relatives are also being treated as significant witnesses.
Durham Police assistant chief constable Michael Banks told a news conference yesterday that a resident at the address was the "lawful holder" of shotgun and firearms licences.
He said these were for three shotguns and three "section one" firearms, a category requiring greater authorisation than a shotgun licence.
The revelation is likely to spark renewed debate over whether to further tighten Britain's gun licensing laws.
Police could not confirm at this stage whether any of those lawfully held weapons had been used in the shooting, Mr Banks said.
He added: "I would like to reassure our communities that the police are in control of this incident.
"At this moment, we are looking for no-one else in relation to this inquiry."
He said that shortly before 11.45pm on Sunday a number of calls were made to the police control room to report that shots had been fired at an address in Greenside Avenue, in Horden, Peterlee.
"Our information within those numerous messages was that several people had been shot," he said.
"The police were dispatched to the scene and shortly after midnight, as our officers entered the house, it was discovered that a man and three women were dead in the house.
"It is our belief at this stage that they died of gunshot wounds."
Mr Banks said of the man found dead in the house: "We believe he may be a member of a gun club. We're still researching that."
Detective Superintendent Paul Goundry said there had been other people in the house who were now being interviewed.
According to reports, Mrs McGoldrick's brother Bobby Hardman said the family was "numb from head to toe", adding: "We've lost three family members in one swoop and that's all I can say really."
Family friend Steve Patterson reportedly said Atherton's brother, Chris, had told him before the shootings that his brother had been suffering from depression.
Mr Patterson was quoted in reports as saying: "He said he was fed up with the way his life was going. I think he started feeling down after an operation he had on his heart."
Neighbours spoke of their shock at the incident.
One woman, who did not want to be identified, said: "I always called them Mike and Sue. I am devastated, totally devastated. Two nice people, I did not think anything like this could happen.
"We are all just shocked, just stunned. There are no other words to describe it. I cannot believe that four people died there."
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more