The families of nine of the 26 people killed at Sandy Hook Elementary School in 2012 have filed a lawsuit against a rifle manufacturer.
The negligence and wrongful death suit was filed in Connecticut against Bushmaster Firearms International.
The families allege the Bushmaster AR-15 rifle used by Adam Lanza, 20, in the incident should not have been made publicly available because it was designed for military use.
Twenty children died in the attack.
“There is one tragically predictable civilian activity in which the AR-15 reigns supreme: mass shootings,” the court documents state.
“Time and again, mentally unstable individuals and criminals have acquired the AR-15 with ease, and they have unleashed the rifle’s lethal power into our streets.”
On December 14, 2012, Adam Lanza killed his mother, Nancy Lanza, before driving to the school and killing 20 children and six adults. He later took his own life when authorities arrived on the scene.
Other defendants in the lawsuit include firearm distributor Camfour and gun store Riverview Gun Sales where Nancy Lanza purchased the AR-15 rifle.
The plaintiffs in the lawsuit include Bill Sherlach, whose wife was killed in the shooting, as well as the families of victims Vicki Soto, Dylan Hockley, Noah Pozner, Lauren Rousseau, Benjamin Wheeler, Jesse Lewis, Daniel Barden, Rachel D’Avino and Natalie Hammond, who was injured in the attack.
“These companies assume no responsibility for marketing and selling a product to the general population who are not trained to use it nor even understand the power of it,” Bill Sherlach told US media.
All 20 children, 12 boys and 8 girls, who died in a shooting at Sandy Hook Elementary School in Connecticut, were aged between six and seven, according to an official list of the dead.
The state’s chief medical examiner said the gunman used a rifle as his main weapon, and all the victims appeared to have been shot several times.
The gunman, named in media reports as Adam Lanza, killed his mother Nancy before driving to the school and opening fire.
Six adults, all women, were also killed before the gunman shot himself dead.
The head teacher at Sandy Hook school in Newtown, Dawn Hochsprung, is listed among the dead, along with adults Rachel DaVino, Anne Marie Murphy, Lauren Russo, Mary Sherlach and Victoria Soto.
The youngest child to be killed was Noah Pozner, who celebrated his sixth birthday only last month.
Most of the children who died on Friday were girls and nearly all were aged six.
Earlier on Saturday, Lt Paul Vance of Connecticut state police said the gunman had forced his way into the school, and had not been let in “voluntarily”.
He said investigators had gathered “good evidence” in the search for a motive.
President Barack Obama is to visit Newtown on Sunday to meet families and speak at a vigil.
After the attack, he urged “meaningful action” against gun crime in the US.
“As a country we have been through this too many times,” he said in an emotional White House address.
The gunman killed his mother at the home they shared before driving to the school in her car and opening fire. Reports say the guns used in the attacks were registered to her.
There are conflicting reports about whether she had worked at the school in the past.
Connecticut Chief Medical Examiner H Wayne Carver said the gunman shot all the victims at the school were shot with a rifle, at least some of them from close range.
Initial reports suggested that the killer had used two handguns which he also had with him.
The suspected gunman’s father, Peter Lanza, said his family was “struggling to make sense of what has transpired”.
“Our family is grieving along with all those who have been affected by this enormous tragedy,” he said in a statement.
Newtown residents have been holding candlelit vigils for Sandy Hook shooting victims
Connecticut Governor Dannel Malloy made a television address saying the children were “taken from their families far too soon”.
“What’s important right now is love, courage and compassion,” he said.
Friday’s killings took place in two rooms within a single section of the school, police have said. The shooting lasted just a few minutes.
As they heard the shots, teachers in other parts of the building tried to protect children by locking doors and ushering them into closets.
“I told them we had to be absolutely quiet, because I was just so afraid if he did come in, then he would hear us and just start shooting the door,” said teacher Kaitlin Roig.
“I said to them, <<I need you to know that I love you all very much and that it’s going to be okay>>, because I thought that was the last thing they were ever going to hear.”
Library clerk Maryann Jacob described telling 18 children to crawl into a storage room, before barricading the door with a filing cabinet.
“We set them up with paper and crayons,” she said.
All 20 children, 12 boys and 8 girls, who died in a shooting at Sandy Hook Elementary School in Connecticut, were aged between six and seven
Dr. Jeannie Pasacreta, a nurse practitioner and psychologist who has been advising parents on how to talk to their children, says neighbors have been cancelling Christmas parties and taking down decorations.
Early reports named 24-year-old Ryan Lanza, of Hoboken, New Jersey, as the gunman, but unnamed officials later said his brother Adam was the suspect.
Ryan Lanza was questioned by police, US media reported, but has not been named as a suspect.
In a separate development, police in Oklahoma have arrested a teenager for allegedly plotting to shoot and bomb students at his school in Bartlesville. Sammie Eaglebear Chavez, 18, is said to have tried to convince other students to help him carry out an attack.
The attack at Newtown is the second deadliest shooting attack at a US school or university.
In 2007, a student at Virginia Tech university killed 32 people and injured many more.
Sandy Hook school shooting victims:
- Charlotte Bacon, 6
- Daniel Barden, 7
- Rachel Davino, 29
- Olivia Engel, 6
- Josephine Gay, 7
- Ana Marquez-Greene, 6
- Dawn Hochsprung, 47
- Dylan Hockley, 6
- Madeleine Hsu, 6
- Catherine Hubbard, 6
- Chase Kowalski, 7
- Jesse Lewis, 6
- James Mattioli, 6
- Grace McDonnell, 7
- Anne Marie Murphy, 52
- Emilie Parker, 6
- Jack Pinto, 6
- Noah Pozner, 6
- Caroline Previdi, 6
- Jessica Rekos, 6
- Avielle Richman, 6
- Lauren Russo, 30
- Mary Sherlach, 56
- Victoria Soto,27
- Benjamin Wheeler, 6
- Allison Wyatt, 6
