Gun stores and ranges toured as agents hunt clues to massacre

Among the questions was: why did Adam Lanza’s mother, a well-to-do suburban divorcée, keep a cache of high-power weapons in their home? What experience did Lanza have with those guns? And, above all, what set him on a path to shoot and kill 20 children, along with the adults who tried to stop him?

Speaking on television, Governor Dannel Malloy said Adam Lanza shot himself as police entered the building.

“We surmise that it was during the second classroom episode that he heard responders coming and apparently at that decided to take his own life,” Malloy said.

He could offer, however, no possible motive for the shooting and a law enforcement official has said police have found no letters or diaries left behind that could shed light on it.

The 20-year-old killer was described as suffering from a personality disorder and being “somewhat autistic” by his older brother Ryan, 24, who was questioned by police who say, however, they believe he had no role in Friday’s tragedy.

Friends and family members have, for their part, said the Newtown High School student was intelligent, nerdy, a Goth and remote.

But none have been able to cast any light on why he might have killed his mother Nancy, shooting her multiple times at their home, before driving to Sandy Hook Elementary School where he blasted his way through the entrance door and then targeted its young pupils and the staff who sacrificed their lives to protect them.

His girlfriend and another friend are still missing in New Jersey.

A spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, told reporters there was no evidence Lanza was involved in gun clubs or had trained for the shooting.

Law enforcement officials have been unable to find any note or “manifesto” of the type they have come to expect after murderous rampages, such as that left behind by killer Cho Seung-Hui after the Virginia Tech bloodbath in 2007 that left 33 people dead.

Education officials too said they had found no link between Lanza’s mother and Sandy Hook, contrary to information from sources on Friday that suggested she was a teacher there.

Investigators said they believe Adam Lanza attended Sandy Hook many years ago, but they had no explanation for why he went there on Friday.

Neither did Lanza have a criminal record.