Adam Lanza was trying to compete with Anders Breivik, a Norwegian man who killed 77 people in July 2011, CBS News reported Monday.
Breivik killed eight people with a bomb in Oslo and then shot 69 others, including many teenagers at an island camp.
Lanza was trying to beat Breivik's death toll and targeted Sandy Hook Elementary because it was the "easiest target" with the "largest cluster of people," unnamed officials told CBS News.
Lanza was reportedly forced to end his shooting spree sooner than planned as police quickly responded to the school.
However, police have denied CBS' report, according to Reuters.
Connecticut State Police Lieutenant Paul Vance told Reuters the report was untrue.