Lanza

HARTFORD, Conn. — A Connecticut agency that investigated the background of the socially isolated, violence-obsessed man who carried out the 2012 massacre at Sandy Hook Elementary School is issuing a report on his mental health and educational history.

The Office of Child Advocate investigates all child deaths in the state for lessons on prevention. In the case of the Newtown shooting, it said its report will focus on the gunman, Adam Lanza, and how his “personal, educational, mental health and medical trajectory can inform public health systems.”

A portrait of the shooter and his fascination with mass killings has emerged in thousands of pages of police documents: Authorities found violentwritings and an arsenal of weapons in the Newtown home where he lived with his mother and spent long hours playing shooter video games.

The police investigation into the massacre concluded more than a year ago with prosecutors saying a motive might never be known. It said Lanza was afflicted with mental health problems, but he did not display aggressive or threatening tendencies.

Lanza killed his mother then shot his way into the Newtown school on Dec. 14, 2012, and gunned down 20 children and six educators before committing suicide.

Documents released by police in December 2013 included descriptions of sporadic treatment for his mental health troubles. At one point, experts at the Yale Child Studies Center prescribed antidepressant/anti-anxiety medication, but his mother, Nancy Lanza, discontinued the treatment after her son was unable to raise his arm after taking the medicine, police reports said.

A Connecticut judge last year ordered Newtown school officials to give Lanza’s records to the Office of Child Advocate for its investigation.