The FBI has just released 1,500 pages of documents that shed more light on the tragic 2012 Sandy Hook Elementary school shooting in Newtown, Connecticut.

Twenty children and six adults were gunned down that day by the shooter Adam Lanza, who then killed himself.

In the wake of the shooting, the FBI assisted local and state police with the exhaustive investigation and the documents released are comprised of field notes of witness statements from Lanza’s neighbors, his life in the weeks and months leading up to the shooting, and more information from his school and medical records.

The trove also contains information gathered from grand jury subpoenas of internet companies Lanza frequently viewed.

There are also accounts of his relationship with his mother Nancy, whom Lanza shot four times and killed just before going to the elementary school.

According to agents’ field notes Lanza led an isolated existence in the months prior to the shooting, only listening to Japanese techno music and playing video games.

He and his mother only communicated via email because he did not leave his room for three months.

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Ms Lanza, according to witness accounts, was worried and planned to move to Seattle the following spring in the hopes it would improve her son’s life.

She had once worked at the school, which Lanza also attended, and one document detailed that "Lanza apparently felt his mother loved the students more than she loved him.”

He also did not leave his house when superstorm Sandy had hit the east coast in October 2012, though the power had been cut for several days.

One set of notes indicated Lanza “had no real friends”.

Heroic Sandy Hook staff saved many lives as the killer struck Show all 9 1 /9 Heroic Sandy Hook staff saved many lives as the killer struck Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff1.jpg Victoria Soto

Victoria’s cousin, Jim Wiltsie, a police officer, said the 27‑year‑old died trying to shield her pupils. “I’m just proud that Vicki had the instincts to protect her kids from harm,” he said. “It brings peace to know that Vicki was doing what she loved, protecting the children, and in our eyes she’s a hero.” Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff2.jpg Avielle Richman

Avielle (pictured in happier times) started first grade at Sandy Hook last August. Her mother Jennifer, whose company sells electrical equipment, attended the same school as a child. Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff3-AP.jpg Dawn Hochsprung

The school principal’s niece, MaryAnn Suarez of Naugatuck, said her aunt devoted her life to schoolchildren. “In every school she worked at, every teacher was her friend. She was every child’s friend.” AP Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff4.jpg Lauren Rousseau

The 30-year-old teacher had just landed her first permanent job as a teacher at Sandy Hook after several years as a substitute teacher. Was due to go out with her boyfriend to the cinema before she was shot. Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff5.jpg Daniel Barden

Known to friends as “Mini” Barden. His elder brother’s football coach confirmed Daniel was among the victims at the school. Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff6.jpg Emilie Parker

Six-year-old Emilie’s parents Robbie and Alissa moved their family from Ogden, Utah, last year after Emilie’s father, a physician’s assistant, found work in the Newtown area. Brad Schultz, a family friend, said Emilie’s body is to be buried in Ogden. Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff7.jpg Mary Sherlach

The school psychologist’s son-in law said: “It was going to be her last year. She loved her job. She’s done this for her whole career. She wanted to help kids get over their problems and go on to be successful.” Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff8.jpg Ana Marquez-Greene

The six-year-old daughter of Canadian jazz saxophonist Jimmy Greene. Her brother Isaiah, who also attended the school, escaped unharmed. Heroic Sandy Hook staff saved many lives as the killer struck 04-heroicstaff9.jpg Jesse Lewis

His father, Neil Heslin, said: “I dropped him off at school at 9am. He went happily. That was the last I saw of him.” Mr Heslin said his six-year-old son had planned to make gingerbread houses in class.

A witness also told agents that the gunman had been bullied in school, but “not excessively,” due to his “social awkwardness” and physical appearance.

Lanza was considered underweight for his height and age at the time of his death.

An online friend, whom he met on a website dedicated to the 1999 Columbine High School mass shooting, called him the “weirdest person online” in one witness interview conducted.

She also noted that Lanza used screen names that were styled to honour mass shooters like German Tim Kretschmer and Canadian Kimveer Gill.

The FBI’s summary of the interview is chilling: "He was singularly focused and obsessed with mass murders … Lanza devoted almost all his internet activity to researching and discussing mass murders and spree killings.”

Lanza also had a prior run-in with the bureau.

When he was in ninth grade, he had hacked through two levels of security into a government computer. The redacted documents did not indicate which agency.