A man who shot himself after killing three women on New Year's Day was a licensed holder of firearms, it has emerged.

The body of the man, named locally as taxi driver Michael Atherton, and those of the three women 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 confirmed that a teenage woman who suffered minor injuries escaped through an upstairs window. Other people in the house at the time also survived, including a man who was initially arrested but later released without charge, police added.

One of the dead women was named locally as Susan McGoldrick.

Police did not release the names of the victims, but Durham Police assistant chief constable Michael Banks told a news conference 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.

"This is a tragic event. We have four people who died late last night and our thoughts and feelings are with their family and friends at this moment," he said.

"At this moment, we are looking for no-one else in relation to this inquiry."

He said that just before 11.45pm yesterday 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."

Detective Superintendent Paul Goundry said all the deceased were related. Police have said that a shotgun was found next to the 40-year-old man's body.

Mr Goundry revealed that police had had "minor contact" with the family previously, in 2008.

Mr Banks said: "There was a report of a male at that address self-harming. That was some years ago. We are researching all of this. There were words. There was nothing came from that."

Mr Goundry added: "In relation to the incident we will be looking to make a voluntary referral to the Independent Police Complaints Commission."

He added that police were working closely with family and friends and a full forensic team was at the house seeking to establish exactly what had happened.

"At this stage we are not looking for anyone else," he said. "It is very early stages in the investigation. My priority is to identify the individuals in the house and I am working very closely with friends and family to establish that."

Mr Goundry said there had been other people in the house who were now being interviewed. The man initially arrested but since released with no further action was being treated as a significant witness.

Mr Banks said of the man found dead in the house: "We believe he may be a member of a gun club."

Neighbours spoke of their shock at the incident.

One woman, who did not want to be identified, said: "I am devastated, totally devastated. Two nice people, I did not think anything like this could happen. I cannot believe that four people died there.

"He [Atherton] was very nice, kind and considerate. We both shared the same drive with our cars and, if he saw you, he would open the gate."

Robert Bailey, 72, a long-standing resident of Greenside Avenue, said he knew the people involved only by sight, and they had appeared "normal, ordinary people".

David Taylor, shooting campaign manager for the Countryside Alliance, said: "The Alliance was saddened to hear of the awful events in Peterlee and our sympathies are with the family and friends of those killed.

"The United Kingdom possesses the toughest and most stringent shotgun licencing laws of anywhere in the world, and the result is that tragic incidents like this one in Peterlee are extremely rare.

"Over half a million people shoot for sport each year and Great Britain will have some of the finest sportsmen and women participating in the shooting events at London 2012.

"The authorities in this country have been careful to find the right balance between public safety and shooting rights, and must ensure that they continue to strike the right balance for everyone's safety."