Search warrants and other documents released by prosecutors show that shooter Adam Lanza fired 154 bullets from his rifle in less than five minutes. NBC News' Michael Isikoff has more.
By Michael Isikoff, Tom Winter and Erin McClam, NBC News
Adam Lanza left a home stuffed with weaponry and carried out the massacre at Sandy Hook Elementary School in a 154-bullet barrage that took less than five minutes, investigators said Thursday in the first detailed account of his surroundings and troubled state of mind.
Search warrants from the second-worst school shooting in American history revealed that the home Lanza shared with his mother in Newtown, Conn., was a veritable arsenal: Authorities found at least nine knives, three Samurai swords, two rifles, 1,600 rounds of ammunition and a 7-foot, wood-handled pole with a blade on one side and a spear on the other.
Authorities also recovered a certificate in Lanza?s name from the National Rifle Association, seven of his journals, drawings that he made and books from the house, including books on living with mental illness.
The warrants offered a thorough look at the environment in which Lanza lived before he shot his mother, Nancy, to death and drove to Sandy Hook on the morning of Dec. 14. Twenty first-graders and six teachers and staff were killed before Lanza shot himself to death with the 155th bullet.
An FBI report based on interviews with people who knew him said that Lanza rarely left home, considered himself a shut-in and was an avid gamer who played ?Call of Duty,? a first-person shooter game. Lanza considered the elementary school his ?life,? the papers said.
Among other items seized from the home were a holiday card containing a check from his mother to buy a firearm, an article from The New York Times about a 2008 school shooting at Northern Illinois University and three photographs of what appeared to be a dead person covered with plastic and blood.
Full list of Lanza arsenal as detailed in search warrants
The books included ?Look Me in the Eye: My Life with Asperger?s? and ?Born on a Blue Day: Inside the Mind of an Autistic Savant.?
At the school, Lanza fired the 154 rounds from a Bushmaster .223-model rifle and the final bullet from a Glock 10mm handgun to take his own life, said Stephen Sedensky, the chief prosecutor investigating the shooting. Police recovered 10 30-round magazines for the Bushmaster that Lanza took to the school. Three of the magazines had a full 30 rounds still in them.
Among school shootings in the United States, the death toll from Newtown is second only to the 32 people killed at Virginia Tech in 2007.
The attack touched off a nationwide debate about gun control. The fate of proposed changes to national gun laws, including expanded background checks and limits on high-capacity magazines, remains unclear.
President Barack Obama spoke Thursday at the White House to make the case again for tougher gun laws. He appeared with parents of Sandy Hook victims and of other gun crimes but did not specifically reference the newly released Newtown warrants.
?The entire country was shocked,? the president said. ?And the entire country pledged that we would do something about it and this time would be different. Shame on us if we?ve forgotten. I haven?t forgotten those kids. Shame on us if we?ve forgotten.?
Connecticut Gov. Dannel Malloy, citing the warrants, also called for stricter gun laws.
?We knew that these weapons were legally purchased under our current laws,? Malloy said. ?I don?t know what more we can need to know before we take decisive action to prevent gun violence. The time to act is now.?
The warrants spelled out a vast inventory of weapons and other gun paraphernalia recovered from the Lanza home.
Among the items found were paper targets, gun manuals, earplugs, holsters, almost 40 types of ammunition, nine types of magazines, a bayonet, knives with blades as long as a foot and Samurai swords with blades as long as 2 feet 4 inches.
Authorities also found a starter?s pistol, a BB gun, an NRA guide to pistol shooting and an NRA certificate in Nancy Lanza?s name.
In a statement, the NRA said it had no record of a ?member relationship? for the Lanzas, nor for someone with the same last name and their first initials.
?Reporting to the contrary is reckless, false and defamatory,? the statement said.
On Wednesday, a judge granted a request from prosecutors to withhold some information in the records, including a witness name, credit card information, telephone numbers and serial numbers.
Besides the Bushmaster and the Glock, authorities found a Sig-Sauer 9mm semiautomatic pistol in the school. In the car outside, police found a shotgun.
All those weapons were legally owned by the mother, authorities have said. Enough public blame and anger has been directed at her that she was left out of many of the memorials and shrines to the Newtown victims.
There have been reports that Lanza was obsessed with other mass killers, including Anders Breivik, who killed 77 people in a shooting and bomb attack in Norway two years ago.
A law enforcement official told NBC News last month that Lanza had collected material on previous mass shootings, although the source said there was no indication that it played a role in the school massacre.
Police told NBC News in February that investigators were still a long way from determining Lanza?s motive. Police said then that they hoped to have a report on the shooting finished by June.
Dec. 14 (first) | Dec. 14 (second) | Dec. 14 (third) | Dec. 15 | Dec. 16
President Barack Obama delivers remarks Thursday at the White House regarding gun reform in America.
This story was originally published on Thu Mar 28, 2013 9:23 AM EDT