HARTFORD, Conn. — A yearlong investigation into the Newtown school shooting has provided disturbing insights into the gunman who killed his mother and then massacred 26 other people, but it still has not provided a motive.
Prosecutors closed the case Monday on the Sandy Hook Elementary shooting last December. Their report offered a chilling portrait of 20-year-old Adam Lanza as a loner who was obsessed with violence and bound by ritualistic behavior.
But they were unable to answer the question that everyone has been asking since the tragedy: Why?
"The obvious question that remains is: 'Why did the shooter murder 27 people, including 20 children?' Unfortunately, that question may never be answered conclusively," the report said.
To try to figure out the motive, investigators said, they interviewed members of Lanza's family — his father and brother cooperated fully — along with teachers and others. They said they also tried within the limits of privacy laws to gather information on his medical treatment.
They found no evidence he had taken any medication that would have affected his behavior or explain the bloodbath.
Lanza "was under no extreme emotional disturbance for which there was a reasonable explanation or excuse," the report concluded.
It said that in fifth grade, Lanza wrote a book that included tales of children being slaughtered and a son shooting his mother in the head.
In the years that followed, he was obsessed with mass murders, assembling articles, photos, books, footage and violent video games, including one in which players gun down students in school. He even kept a spreadsheet ranking mass murders.
The summary released by the lead investigator, State's Attorney Stephen Sedensky III, describes Lanza as having "significant mental health issues" but sure knowledge of what he was planning: Besides having the spreadsheet, he smashed his computer hard drive and used earplugs during the shooting.