Sydney, Feb. 18 (ANI): Adam Lanza, the fanatic who shot six adults and 20 kids at Sandy Hook Elementary School, may have been emulating a video game when he carried out his deadly assault in December last year.

Investigators probing the massacre are exploring the theory that his video games are a vital clue to his actions.

During a search of the home that Lanza shared with his mother, Nancy Lanza who walled killed by her son before carrying out the deadly assault in school, police found thousands of dollars' worth of graphically violent video games, news.com.au reports.

Before his killing rampage Lanza, 20, destroyed the hard drive on his computer, which may have kept some of the records of the games he played and who he played with.

It is unknown whether Lanza had left a manifesto or other written explanation for the shootings or why he chose the school.

According to the report, Lanza carried three of his mother's guns, dressed in black and wore a utility vest with pockets stuffed with ammunition during the rampage. He later killed himself.

Even back in kindergarten Adam had been identified as needing an 'individual education plan' and extra attention in the classroom and at home.

When Lanza was a teenager, his mother told a Newtown High School staff member that her son had Asperger's and had also been diagnosed with sensory integration disorder, which meant he had difficulty coping with loud noises, bright lights, confusion, and change, the report said.

In 2009 Lanza's parents divorced and the following year he became estranged from his father, Peter Lanza.

According to the report, after the divorce, Nancy Lanza traveled more, leaving Adam alone for days at a time, something, she told friends, she was doing to encourage him to be more independent.

Nancy Lanza had bought four firearms between 2010 and 2012. During that time she took both Lanza and her oldest son, Ryan, target shooting at a gun range, it added. (ANI)