The man suspected of killing over 20 people at a US school was an honours student who lived in a prosperous neighbourhood with his mother.
Adam Lanza is accused of killing his mother at their home before driving her car to Sandy Hook Elementary School and - armed with at least two handguns - killing 27 people there. Among the dead were 20 children aged 5-10 years.
Lanza was also found dead at the school by authorities, who later discovered a third weapon, a .223-calibre rifle, in Lanza’s mother’s car. More guns were also found inside the school.
The 20-year-old may have suffered from a personality disorder, law enforcement officials said.
Investigators were trying to learn as much as possible about Lanza, but so far authorities have not spoken publicly of any possible motive. Witnesses said the shooter didn’t utter a word.
Catherine Urso, who was attending a vigil Friday evening in Newtown, Connecticut, the scene of the massacre, said her college-age son knew the suspected killer and remembered him for his alternative style.
‘‘He just said he was very thin, very remote and was one of the goths,’’ she said.
Lanza and his mother, Nancy, lived in a well-to-do part of Newtown, a prosperous community of 27,000 people about 100km northeast of New York City.
A grandmother of the suspect - who is also the mother of Nancy Lanza - was too distraught to speak when reached by phone at her home in Florida.
‘‘I just don’t know, and I can’t make a comment right now,’’ Dorothy Hanson, 78, said in a shaky voice as she started to cry.
A law enforcement official speaking on condition of anonymity said investigators believe Lanza attended the school several years ago, but appeared to have no recent connection to the place.
At least one parent said Lanza’s mother was a substitute teacher there. But her name did not appear on a staff list. And the law enforcement official said investigators were unable to establish any connection so far between her and the school.
Adam Lanza’s older brother, 24-year-old Ryan Lanza, was being questioned, a law enforcement official said.
He told authorities that his brother was believed to suffer from a personality disorder, the official said, speaking on condition of anonymity because he was not authorised to speak on the record about the unfolding investigation.
The official did not elaborate, and it was unclear exactly what type of disorder he might have had.
Ryan Lanza had been extremely cooperative and was not under arrest or in custody, but investigators were still searching his computers and phone records. Ryan Lanza told law enforcement he had not been in touch with his brother since about 2010.
Earlier, authorities mistakenly named Ryan as the suspected killer owing to a mistaken transposing of names.
Brett Wilshe, a friend of Ryan Lanza’s, said he sent him a Facebook message Friday asking what was going on and if he was okay.
According to Wilshe, Lanza’s reply was something along the lines of: ‘‘It was my brother. I think my mother is dead. Oh my God.’’
Adam Lanza attended Newtown High School, and several local news clippings from recent years mention his name among the school’s honour roll students.
Sandeep Kapur, who lives two doors down from the Lanza family in Newtown, said he did not know them and was unaware of any disturbances at the Lanza house in the three years that he and his family have been in the neighbourhood.
He described the area as a subdivision of well-tended, 15-year-old homes on lots of an acre or more, where many people work at companies like General Electric, Pepsi and IBM.
Some are doctors, and his next-door neighbour is a bank CEO, said Kapur, a project manager at an information technology firm.
‘‘The neighbourhood’s great. We have young kids, and they have lots of friends,’’ he said.
‘‘If you drive past this neighbourhood, it gives you a really warm feeling.’’
The rampage in the northeastern state of Connecticut was at least the fourth big shooting spree in five months in the United States. It was by far the deadliest of the year and the most heart-wrenching.
The children, aged 5-10 years, were among the youngest victims of a mass shooting in recent history.
The chaos struck Friday (local time) as children gathered in their classrooms for morning meetings.
Police swarmed the scene and locked down the school, rushing children to safety, some of them bloodied.
Distraught parents converged, frantically searching for their daughters and sons.
Neighbours and friends wandered in shock, looking for information.
''It's hard to believe that anything like this could happen in this town,'' said resident Peter Alpi, 70, as he fought back tears.
''It's a very quiet town. Maybe it's too quiet.''
'EVIL HAS VISITED'
US President Obama has gone on national television to express "overwhelming grief'' at the tragedy.
His sentiment was echoed by American politicians the nation over.
''Evil visited this community today,'' Connecticut Governor Dannel Malloy told reporters.
"There is not a parent in America who does not feel the same overwhelming grief that I do,'' Obama said.
An emotional Obama said that as a country, the US had been through shootings like this too many times and pledged "meaningful action'' on the issue "regardless of politics''.
"Our hearts are broken today,'' Obama said. He said it was possible the toll could go higher.
Mergim Bajraliu, a 17-year-old high school student, said he was at his home nearby when he heard two shots. He and a neighbour ran to the school to find his 9-year-old sister, Venesa.
"My heart sank," he said, describing seeing two students covered in blood being carried out of the building, one of whom looked like his sister. To his relief, his sister later emerged unharmed, and Bajraliu greeted her with a hug.
"I was like, 'Oh my God," Bajraliu said.
Home to about 27,000 people, the wealthy, wooded town of Newtown is in southeastern Connecticut, about 130 km northeast of New York City.
It is a so-called bedroom community, with many homes situated on multiple acres of land and residents commuting to larger cities including Hartford and Stamford.
"You can never be prepared for this kind of incident," Connecticut Governor Dannel Malloy told reporters.
"What has happened, what has transpired at this school building will leave a mark on this community and every family impacted."
Messages of condolence have poured in to the US from abroad.
British Prime Minister David Cameron said ‘‘it is heartbreaking to think of those who have had their children robbed from them’’.
Queen Elizabeth sent a message to Obama saying she was saddened by the ‘‘dreadful loss of life’’.
The US Ambassador to New Zealand and Samoa, David Huebner, expressed his deep condolences too.
"I am shocked and overwhelmed by this horrendous tragedy. My thoughts and prayers are with the victims, their families, and all affected by the shooting.
“I would like to thank New Zealanders for their expressions of sympathy and condolence to America on this tragic day."
In a public statement addressed to Obama, French President Francois Hollande said he was ‘‘horrified’’.
ILLUSIONS OF SAFETY SHATTERED
Local churches quickly organised evening memorial services to help residents cope with the trauma that shattered their illusions of safety.
"I don't think you are safe anywhere," said Lori Amaral, who lives about 400 metres from the school. She added that her college-age daughter and her friends were afraid even to go out to the vigil.
"They are afraid to go anywhere," Amaral said.
John Hess was at the airport in Cleveland morning when his wife, Patty, called him to tell him about the shooting. He immediately hopped a plane home to Newtown, where his family moved recently from nearby Stamford.
"We moved here because we thought it would be a safe community," Hess said.
'IN A DAZE'
Parents of children at the school for children aged 5 to 10 years gathered at a fire station down the street from the school building to await news of their children.
Helicopters hovered over the school building and scores of cars were parked on lawns up and down the street, reflecting the hurried response of police, parents and officials after the shooting took place around 9:30am local time (1.30am).
"Everybody was crying," said Alexis Wasik, 8, a third-grader who was in the school when the shooting began. "I was a little scared and felt sick to my stomach."
The attack was the deadliest mass shooting at a US school since a 2007 sniper attack at Virginia Tech left 32 people dead.
"I am still in a daze," said Alexis' mother, Lynn. "My heart is in a million pieces for the children."
Juanita Hall, a school counselor in nearby Ridgefield, whose daughter attends the school, said it would take time for the residents to recover from the shock.
"The most difficult thing is to have a conversation with the children about this. My immediate thoughts were about Columbine," Hall said, referring to a 1999 incident in which students at a Colorado high school killed 13 students and staff.
"It's going to take a very long time for this community to get over this, if it's even possible. I'm not sure it's even possible."
- Subsequent stories have reported an updated figure of 26 dead.