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.
"I want to go home," she whimpered.
Moments later, Vanghele and another officer, Sgt. William Cario, discovered a classroom where they found what appeared to be about 15 bodies, mostly children, piled in a small bathroom "like sardines."
Vanghele surmised that when the teachers heard gunshots, they ordered the children to cram into the bathroom. There were so many people inside that the door couldn't be closed, and the shooter gunned them all down.
Cario said he later helped three paramedics inside the school, saying he tried to select ones he knew had the experience to deal with the horrific scene.
He said he told one of them, "This will be the worst day of your life."
A JANITOR INTERVENES
Sandy Hook teachers described seeing janitor Rick Thorne rush toward the front of the school after the first shots. One teacher who couldn't get her classroom door locked told investigators that she looked into the hall, saw Thorne and motioned to him to lock her door. Other teachers who were hiding in their rooms heard Thorne confront Lanza, including telling him, "Put the gun down!"
Thorne said he called 911 from a school cellphone, told teachers to stay in their rooms and began locking classroom doors.
When police encountered Thorne, he couldn't produce his school ID, so he was handcuffed. But Thorne gave police the keys to the school and told them how to get up on the roof before he was escorted out of the building.
A TEACHER ASKS FOR A BADGE
Teacher Kaitlin Roig told police she heard "rapid fire shooting" near her classroom. She rushed her students into the classroom's bathroom, pulled a rolling bookshelf in front of the bathroom door and then closed and locked the door.
Roig packed 15 children in the bathroom, placing the smallest on the toilet paper dispenser for a moment and holding her there with one arm while she positioned the others. At one point, five or six children were piled on the toilet. The children knew what was happening and told her, "bad guys were shooting." Roig told the children they just had to wait until the good guys arrived.
Roig heard more gunfire, which seemed to be coming from the hallway outside her room and then heard a voice say, "Oh, please, no. Please, no."
Eventually, police officers slid their badges under the bathroom door. Roig refused to come out and told them that if they were truly police, they should be able to get the key to the door -- which they did.
A GREAT HIDING PLACE
Trooper Ken Cournoyer, who helped evacuate children from the closets where they'd been hiding, recalled one boy who emerged and said he had a very good hiding spot.
"I remember him being so proud of himself for hiding so well," Cournoyer wrote in an investigative report. "I thought to myself that the teacher did a great job of distracting the children from what was actually taking place."
POLICE INTERVIEWED CHILDREN WITH CARE
Police were cautious when interviewing children who survived. The interviews were done only if the children or their parents requested them. If the child didn't want to talk, the interview was ended immediately.
Some of the parents thought talking openly about the shooting and getting accurate information out would help their child heal.
Detectives showed the children a simple map of the school's entrance, including the first grade hallway, and told them police knew Lanza came in through the glass doors and started walking down the hall shooting.
After the interview, the children were given a copy of Margaret Holmes' book "A Terrible Thing Happened" to help them process the violence they had witnessed.
IDENTIFYING THE DEAD
The documents contain dozens of reports from officers who notified the families of victims that their loved one had been formally identified.
Despite the reports' dispassionate, professional tone, the details hint at the day's horror. Officers wrote about returning coats, lunchboxes, artwork and clothing that belonged to victims. Some families were eager to reclaim their children's belongings; others said they weren't ready.
One officer wrote that he and a Catholic priest visited a victim's family. "Father Novajosky offered a prayer ... which they gladly accepted," he wrote.