Adam Lanza was fascinated with chimpanzees because of their capacity for empathy, but could show little or none himself.
He could write stories that struck horror into a teacher's heart, then craft a poem so beautiful it moved listeners to tears.
As a child in Connecticut, he rode bikes, played baseball and saxophone and kept hamsters. As a man, he taped black garbage bags over his bedroom windows, retreating into a world of video games, guns and statistics on mass murder.
Despite the release Friday by Connecticut state police of thousands of pages of interviews, photographs and writings, the man who gunned down 20 first-graders and six adults at Newtown's Sandy Hook Elementary School on Dec. 14, 2012, remains an enigma.
Some of the most tantalizing evidence of the workings of the 20-year-old Newtown man's brain appears to be contained in writings the police chose not to release.
An eight-page document titled "me" is described in a police inventory as "detailing relationships, ideal companion, culture, voting, personal beliefs, describes doctors touching children as rape." Another, titled "tomorrow," apparently contains details about the author's "desires, list of the benefits of being thin and negative connotations associated with being overweight, list of goals ..."
What the files show is a troubled young man, living with a single mother unable or unwilling to accept the depths of his illness.
Childhood photos of Adam Lanza show a smiling boy who could look into a camera, but signs of trouble emerged early.
During his preteen years, Lanza had difficulty with speech and was "being followed medically for seizure activities," according to investigators.
"In preschool his conduct included repetitive behaviors, temper tantrums, smelling things that were not there, excessive hand washing and eating idiosyncrasies," prosecutors said in one report.
Lanza's real problems appear to have begun after his parents' separation in 2001, when he was 9.
Adam had attended Sandy Hook Elementary. In fifth grade, he turned in a story about a "chicken tree" whose hen fruit "contains everything you ever will need to live like calcium and water."
"It spits out seeds every four hours by using its long chute," he wrote. "The vines that holds the chicken is very soft and very strong."
That same year, Lanza produced a more disturbing work.
According to a boy who worked on it with him in class, "The Big Book of Granny" was supposed to be a "comic-style book" in the vein of "Calvin & Hobbes." In a section labeled "Granny's Clubhouse of Happy Children," typed as dialogue from an imaginary television show, Granny and her son, "Bobolicious," terrorize a group of children. In one episode, Bobolicious tells the children they're going to play a game of "Hide and go die."
Granny uses her "rifle cane" to kill people at a bank, hockey game and Marine boot camp. She goes back in time and murders the four Beatles, according to a police synopsis.
The book contains several chapters with the adventures of "Dora the Beserker" and her monkey, "Shoes" -- a knockoff of the children's show "Dora the Explorer."
When Granny asks Dora to assassinate a soldier, she replies: "I like hurting people ... Especially children." In the same episode, Dora sends "Swiper the Raccoon" into a day care center to distract the children, then enters and says, "Let's hurt children."
In the real kids' show, Dora has a backpack that contains a talking map. In Lanza's version, the group carries a bag stuffed with an AK-47, an M-16, a shotgun, a musket and a rocket launcher.
The boy who drew the cover illustration -- showing Granny firing her cane gun -- thought the book was turned in, but that is unclear.
He told investigators Lanza was "weird" and "would sit by himself on the other side of the room and would not talk or associate with anybody else." Lanza came to school with a briefcase, he recalled.
One poem contained in the police files is titled, "No frogs, No kids":
"Too many ants are coming.
Ants over populate.
Ants dig dirt.
dirt grows plants.
Bees come to plants.
Cock Robin died.
Bees die.
ants feed bees to babies.
Ants will overtake to win.
One baby died.
3 eggs won't hatch.
one bird has no voice."
By seventh grade, a teacher told investigators, Lanza's writing was "so graphic that it could not be shared" except with the principal. The teacher said Adam's parents were not "upfront" about his mental abilities.
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."
But when the teacher asked Adam to submit something else to share with the class, he produced a lovely poem.
"Adam shared his poem in public with his father present, who was in tears," the teacher told police.
Peter Lanza has declined to speak publicly about his son. But in interviews with investigators, he said his son's life appeared to take a turn after his 11th birthday.
He seemed "less happy, stressed and frustrated," his father said, but he never exhibited any "outward signs of anger or aggression." He told people he "did not think highly of himself and believed that everyone else in the world deserved more than he did," according to investigators.
Dr. Robert A. King, a professor at the Yale School of Medicine Child Study Center, conducted a three-hour psychiatric evaluation of Lanza in 2006. King diagnosed Lanza with "profound Autism Spectrum Disorder, with rigidity, isolation, and a lack of comprehension of ordinary social interaction and communications."
Peter Lanza told police his son had Asperger's syndrome, a type of autism not associated with violence.
King said Lanza displayed symptoms of obsessive-compulsive disorder. The boy would change his socks 20 times a day and sometimes would go through a box of tissues in 24 hours because he couldn't bear to touch a doorknob with his bare hand.
Kathleen Koenig, an advanced practice nurse at the Yale Child Study Center who conducted four interviews with Adam Lanza in 2006 and 2007, described him as "emotionally paralyzed."
Koenig said she prescribed him with an antidepressant/anti-anxiety medication. She said the mother's response to her recommendations for Lanza as "non-compliant."
After prescribing Lanza a "small dose" of the drug, the nurse said, she received a call from Nancy reporting 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.
When Adam missed an appointment, Koenig said, his mother "failed to schedule" any follow-up visits.
His freshman year, Lanza's mother withdrew him because of "stresses over papers, classes, pressure from grades and dealing with his disease," an acquaintance told police. But that same person told authorities Lanza "never completely accepted that he had a disease."
Peter Lanza told the investigators his ex-wife decided to home-school Adam, because he seemed more comfortable that way. But while their 2009 divorce file shows an amicable split, the newly released documents suggest the couple had differences over how Adam was being raised.
In a February 2007 email to a doctor, Nancy Lanza wrote: "I have been more concerned with keeping him as comfortable as possible and just getting through each day." His father, on the other hand, was focused on "stabilization."
Peter Lanza told police his and Adam's relationship "deteriorated" in late 2010, and his son eventually stopped responding even to emails. Adam's older brother, Ryan, hadn't had any contact with him since 2010.
Two weeks before the shootings, the documents say, Nancy Lanza told a friend Adam was growing "increasingly despondent" and had refused to leave his room for three months. They communicated only via email; one document in the police inventory is a "list of problems and requests from the shooter to Nancy."
The only thing they seemed to have in common was a love of guns. Nancy and Adam took a firearms safety course together, and she took him to a range to fire some of the weapons she kept at home.
But Nancy Lanza told a friend she asked her son whether he would feel bad should anything happen to her, and he replied, "No."
But as one person told the FBI: "Nancy was not afraid of Adam, but was afraid for him." Still, she was trying.
On Dec. 10, 2012, she decided to try a little "experiment." She was going to make a short trip to New Hampshire to see how Adam fared alone for a few days.
Shortly before noon, she texted a friend "she had gotten off to a rough start." Adam had "bumped his head" that morning, and they were "dealing with blood," according to the police files.
Nancy Lanza returned home the evening of Dec. 13.
Within 12 hours, she, her son and 26 others were dead.
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