The man who killed 26 people including 20 children in an attack on Sandy Hook Elementary School almost a year ago acted alone and his motive may never be known, investigators say.
A state attorney's report said that the criminal investigation into the shooting by 20-year-old Adam Lanza, who murdered his mother before attacking the school and ended the rampage by turning his gun on himself was now closed and no charges will be brought.
Investigators said there was evidence that Lanza planned his rampage, but did not discuss his plans with others.
"The obvious question that remains is: 'Why did the shooter murder twenty-seven people, including twenty children?' Unfortunately, that question may never be answered conclusively," the report said.
While the large informal memorials that arose in the Connecticut town of 27,000 residents in the days after the shooting have long been removed, small commemorations are sprinkled throughout the sprawling town.
Last year, on the morning of December 14, Lanza shot and killed his mother, Nancy Lanza, in her bed in their Newtown home, and then forced his way into Sandy Hook, which he once attended.
In a series of emails to Newtown parents last week, John Reed, the town's interim schools superintendent, addressed the report's release and cautioned parents to be mindful of their children's' emotional well-being.
"By supporting one another, we will work our way through these challenging circumstances," Reed said.
A Connecticut law passed earlier this year said that some evidence from the state's investigation would never be made available to the public.
The law, passed in response to the shooting, prohibits the release of photographs, film, video and other visual images showing a homicide victim if they can "reasonably be expected to constitute an unwarranted invasion of personal privacy of the victim or the victim's surviving family members."