December 27, 2013 at 11:25 AM EST - Updated July 21 at 8:16 AM
By JOHN CHRISTOFFERSEN Associated Press
NEW HAVEN, Conn. (AP) - The planned release Friday of thousands of pages of police documents from the investigation into last year's school massacre in Newtown could shed light on the world of the 20-year-old gunman.
State police said their report totaling several thousand pages would be released at 3 p.m. The report "has been redacted according to law," and includes text, photos and 911 calls received by state police, they said Thursday.
Prosecutors issued a summary of the investigation last month that portrayed the gunman, Adam Lanza, as obsessed with mass murders, but the report concluded that Lanza's motives for the massacre might never be known.
The summary report referred to items found on a computer at Lanza's house that included writings detailing relationships, personal beliefs, a daily schedule, desires, goals and other topics.
Lanza gunned down 20 first-graders and six educators with a semi-automatic rifle at Sandy Hook Elementary School on Dec. 14, 2012, after killing his mother inside their home. He committed suicide with a handgun as police arrived at the school.
The summary says Lanza had "significant mental health issues."
The report said that in 2005, Lanza was diagnosed with Asperger's disorder, a mild form of autism that is not associated with violence, and that he lacked empathy for others and behaved strangely. Nobody was allowed into his room, he wouldn't touch doorknobs, his food had to be arranged on the plate in a certain way and he changed clothes often during the day, according to the report.
In fifth grade, Lanza wrote "The Big Book of Granny," in which the main character has a gun in her cane and shoots people, and another character talks of liking to hurt people, especially children. The book was among items seized from Lanza's home, but there was no indication he ever handed in the book at school.
Lanza became obsessed with the 1999 bloodbath at Columbine High in Colorado and other mass killings, the report said. He even kept a spreadsheet ranking mass murders.
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.