NEW YORK // The gunman who murdered 20 children and six adults at a Connecticut elementary school in December may have been motivated by the desire to beat the death "score" of Anders Breivik who killed 77 people in Norway in 2011.
Law enforcement officials involved with the investigation into the shooting at Sandy Hook Elementary school in Newtown, Connecticut, said that Adam Lanza, 20, selected the school because it offered the "easiest target" with the "largest cluster of people".
The connection to Breivik is based on newspaper reports about the anti-Muslim extremist that investigators found in Lanza's bedroom and that is still only a theory, law enforcement officials told the Hartford Courant on Monday.
But Connecticut police who last week travelled to Washington to brief federal authorities on the current status of the investigation discussed the Breivik angle.
Breivik, who called himself a warrior defending Christian Europe from Muslim immigration, bombed the government headquarters in Oslo, killing eight people, before shooting dead 69 youths at the ruling party's island summer camp.
He was sentenced to the maximum 21 years in prison last year.
Lanza took his own life as police officers responded to his assault on the school but investigators do not suspect that he shared the same ideology as Breivik.
The investigation into the December 14 shootings will probably take until the summer to complete, said Stephen Sedensky, the state's attorney in Danbury, Connecticut, who heads the inquiry.
Two months after the killings at Sandy Hook, police have offered no official motive, but have recently made significant strides.
Investigators have been able to restore one of the computer hard drives that Lanza tried to destroy before he set out to attack the school, which led them to people who had been in contact with him through online video games.
Lanza spent hours playing video games in a basement gaming room with blacked-out windows, where investigators found a large number of violent games.
There has been growing speculation about the role violent video games played in the rampage, with the officials telling CBS that Lanza was likely acting out a video game-fuelled fantasy with each death a "score".
In a documentary that was broadcast yesterday on Frontline, an investigative journalism programme on public television, police were reported as saying that, in the shooting spree, Lanza acted in ways consistent with how video games are played, changing his weapons' ammunition magazines frequently and before they were empty.
While it will probably prove difficult to make any definitive connections between video games and Lanza's violence, the documentary shed light on aspects of his childhood and mental health that could also have been part of the combination of factors that led to the shooting tragedy.
Lanza had been identified as a child with a "sensory integration" disorder that caused him to not know when he was in pain, as well as suffering from Asperger's, a disorder that can make social interaction difficult, Frontline reported.
A teacher who ran a tech club that Lanza joined in high school told the programme that the boy would have "episodes" where he would sit motionless in a corner.
His mother, Nancy Lanza, whom Lanza shot to death as she slept before he set out for Sandy Hook, never feared that her son was violent, and the pair bonded over sessions at a local shooting range.
While the gun-owning mother has been portrayed as partially responsible for Lanza's rampage, friends and acquaintances said that "her life revolved around caring for Adam", and helping him to adjust to her divorce from his father. Others said that she was in the last stages of planning to move with her son as he attended college.
* With additional reporting by Reuters