Sandy Hook Elementary School killer Adam Lanza’s anti-social and emotional problems began presenting in grade school but teachers failed to notice, concludes a yearlong study by the Connecticut Office of the Child Advocate that was issued Friday. And though the researchers say they didn’t set out to address the gun issue, it was difficult not to question Lanza’s continued access to and interactions with firearms.

“It was not the primary purpose of this investigation to explicitly examine the role of guns in the Sandy Hook shooting,” said the report written by a team of specialists led by state Child Advocate Sarah Healy Eagan. “However, the conclusion cannot be avoided that access to guns is relevant to an examination of ways to improve the public health.”

The report concludes that Lanza’s parents, school administrators, teachers and mental health professionals all failed to recognize the severity of his mental deterioration, and it recommends more resources be devoted to universal screening for behavioral and developmental problems in children starting at birth.

On Dec. 14, 2012, Lanza, 20, took his Bushmaster semi-automatic rifle and a Glock nine millimeter handgun and murdered his mother Nancy in their home, and then six teachers and 20 first-graders at the school before taking his own life. The shooting rocked the small community of Newtown, Connecticut, and it reignited a national gun control debate.

According to the researchers, Lanza’s last interaction with mental health specialists occurred six years earlier when the Yale Child Study Center in New Haven warned Nancy and Peter Lanza that without treatment their son's mental condition would deteriorate and lead to a life of “dysfunction and isolation.”

Peter, who separated from Nancy in 2002 but maintained joint custody of their son, said he tried to seek treatment but Adam resisted. Nancy not only helped her son resist treatment but also helped him acquire firearms, and both parents continued to nurture his use of weapons into his teens through recreational shooting activities.

Nancy was also struggling with a belief that she was suffering from a terminal health condition as far back as 1999 despite unremarkable medical test results. The report suggests this preoccupation with her own health may have blinded her to the real symptoms her son was exhibiting.

Lanza’s teachers, too, failed to see his deteriorating psychiatric condition. As reported earlier, Lanza co-authored a school writing project called “The Big Book of Granny” that graphically details child murder, cannibalism and taxidermy. The writings appear to have been professionally bound, suggesting an adult assisted in assembling the presentation.

“There is intense violence featured in this book, and authors conclude that it was not the sort of creation that most children would even know to invent,” the report stated. But despite the abhorrent nature of the work, the report says there was no clear indication in the educational records that school staff were aware of the contents.

Read the full report here