Connecticut State Police released thousands of pages of documents from the investigation into last year's massacre at Sandy Hook Elementary School in Newtown.
The documents released Friday provide the most detailed and disturbing picture yet of the Dec. 14, 2012, rampage that left 20 first-graders and six adults dead. They also provide some insight into gunman Adam Lanza's fascination with murder but stopped short of providing a clear motive, which prosecutors said might never be known.
Here are some key findings found in the documents:
ADAM LANZA INCREASINGLY DESPONDENT
A woman who identified herself as a lifelong friend of Lanza's mother, Nancy, told an investigator that Nancy Lanza had visited her about two weeks before the shooting. The woman, whose name is redacted, said Nancy Lanza told her Adam Lanza was becoming increasingly despondent.
The woman said he hadn't left his room in three months and was communicating with his mother only via email, despite them sharing a home, and that Nancy Lanza felt sorry for him.
The woman said Nancy told her Adam had no emotional connection to his mother and that when his mother asked if he'd feel bad if something happened to her, he replied no. Still, Nancy expressed no fear for her safety, the woman said.
LANZA'S FATHER: LITTLE CONTACT
Peter Lanza, Adam Lanza's father and Nancy Lanza's ex-husband, told investigators he was estranged from his son and would send emails that generated no response. The father said he continued to invite Adam to go with him to events he thought he might enjoy — coin shows, arcades and shooting ranges.
Peter Lanza said Adam Lanza was a "happy kid" when he was 8 or 9 and a student at Sandy Hook Elementary. But he noticed a change in Adam's behavior once his son turned 11. Adam seemed "less happy, stressed and frustrated," according to his father, but he never exhibited any "outward signs of anger or aggression."
He said his son rarely left the house and that his primary social interaction came from online gaming.
Among the many items police found when they searched the Lanza home was an undated birthday card from Peter Lanza.
"Send me an e-mail when you want to go hiking or shooting," Peter Lanza wrote. "Love Dad."
DOCTOR, NURSE CITE PROFOUND AUTISM DISORDER
Dr. Robert A. King, a professor at the Yale School of Medicine Child Study Center, conducted a three-hour psychiatric evaluation of Adam Lanza in October 2006. He referred Lanza to Kathleen A. Koenig, an advanced practice registered nurse at the Yale Child Studies Center, who conducted four face-to-face interviews with Lanza.
King and Koenig each concluded Lanza had profound autism spectrum disorder, but King told investigators that he observed nothing in Lanza's behavior that would have predicted that he would have become a mass killer.
Koenig described Lanza as "emotionally paralyzed" because of debilitating obsessive compulsive disorder, which led him to change his socks 20 times a day.
After prescribing Lanza a "small dose" of antidepressant/anti-anxiety medication, the nurse said, she received a call from Nancy Lanza reporting that he was "unable to raise his arm." Koenig didn't believe the medication could cause such a side effect, but Nancy Lanza did and discontinued the treatment.
Lanza later skipped an appointment and didn't schedule follow-ups.
TEACHER SAW AN OBSESSION WITH VIOLENCE, WAR
One of Lanza's former teachers told investigators that his writing was "so graphic that it could not be shared" — except with the principal. Adam would write essays "obsessing about battles, destruction and war," said the teacher, whose name and gender were redacted.
"In all my years of experience, I have known ... boys to talk about things like this but Adam's level of violence was disturbing," the teacher said.
The teacher forced Lanza to write something that he could share with the class. "He wrote a poem, from what I recall was beautiful," the teacher said. "Adam shared his poem in public with his father present, who was in tears."
OFFICERS RECOUNT HORROR
Police Lt. Christopher Vanghele, one of the first officers inside the school, remembered smelling gunpowder in the air as he huddled with two other officers, unsure where the shooter was. Suddenly a little girl walked out of a classroom alone.