By Matt Flegenheimer

New York Times News Service

Authorities in Connecticut released a final report Friday outlining the shooting at Sandy Hook Elementary School in Newtown on Dec. 14, 2012, providing the most complete account to date for one of the nation’s most wrenching massacres. It contained hundreds of photographs, hours of video and voluminous crime scene reports.

Care was taken to conceal the most graphic crime scene images. Yet painfully detailed descriptions accompanied the often-redacted pages, relaying eyewitness accounts from students and school staff members, and snapshots of emergency workers dashing to locked doors, at times straining to convince terrified teachers on the other side that they were officers.

There were new details concerning the gunman, 20-year-old Adam Lanza, who killed 20 first-graders and six adults in the school. Lanza also killed himself and his mother, Nancy, who told an acquaintance the day before the shooting that she had traveled to New Hampshire for a brief trip as “an experiment to allow Adam to stay at home alone for a few days,” the documents said.

The report also included many photographs of the contents of their house, including one of a young child holding what appears to be a gun, with ammunition in his lap.

Lanza’s father, Peter, who was divorced from Nancy Lanza, appeared in sharper focus, too: He supplied documents that included resources he had sought out about autism and Asperger’s syndrome, which his son reportedly had. There was also a birthday card, signed “Love, Dad,” with an offer to take his son “hiking or shooting.”

Then there were the reports about the families of the victims, some of whom, less than a month later, could not yet bear to receive the belongings their children had left behind. Other loved ones asked to tour the school.

For all its material, the report did not appear to alter the broader understanding of the shooting, for which the authorities have not established a clear motive.

The state’s Department of Emergency Services and Public Protection said the release of the full report was “indicative that this State Police criminal investigation is concluded.”

Questions of how and when to release sensitive investigative details from the shooting have been prevalent since shortly after the massacre.

In a letter accompanying the report, Reuben Bradford, the commissioner of the state’s Department of Emergency Services and Public Protection, said the names and “contextually identifying information of involved children” were withheld.

“All visual images depicting the deceased have been withheld,” he added, “as well as written descriptions whose disclosure would be highly offensive to a reasonable person and would violate the constitutional rights of the families.”

Bradford said that balancing the “often competing interests of government transparency and individual privacy has been difficult.”

The records’ release Friday followed a far shorter report last month from the office of Stephen Sedensky, the state’s attorney in Danbury, which focused in large measure on the home that Lanza shared with his mother.

At the time, the account provided the most detailed report yet about Lanza’s final months — his bedroom windows covered with black trash bags, as he was preoccupied with video games and communicated with his mother only through email, even though they were on the same floor.

According to the new report, Nancy Lanza traveled to New Hampshire on Dec. 11 and returned on the evening of Dec. 13. During a lunch in New Hampshire with an acquaintance, the interviewee said, Nancy Lanza “described a difficult life but gave him the impression that she was courageous and ‘handling everything.’”

She added that she “accepted the obligations of caring for Adam” and was “very proud of Adam’s accomplishments,” the acquaintance said.

Other interviews sketched a more complete portrait of the gunman. He could play the saxophone, the documents said, and had taken private lessons in Mandarin. Writings recovered from his computer included two fictional works about being attacked by babies and a screenplay or script called “Lovebound,” describing a relationship between a 10-year-old boy and a 30-year-old man.

“The shooter had recently begun to drive,” another entry read, “after previously not wanting to get his driver’s license.”

The report also included the most exhaustive information yet from inside the school, where Lanza blasted through the glass windows at a locked entrance around 9:34 a.m. (By 9:40, the police said, he had shot himself in Classroom 10, a first-grade room.)

Although the names, physical descriptions and belongings of adults were included, information about the children was omitted, even as the macabre scenes were relayed in detail. The victims were first identified using numbers, 3 through 26. Lanza was assigned the number 27. “Once all the victims were removed from the school,” one document read, “only the shooter’s body remained within the scene.”

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