The gunman behind the shooting massacre at Connecticut’s Sandy Hook Elementary School reportedly compiled extensive research about previous mass murders into a spreadsheet containing roughly 500 people.

The New York Daily News reports that an obsessive Adam Lanza produced a spreadsheet 7 feet long and 4 feet wide in tiny 9-point font that required a special printer on past mass killings and attempted murders.

“We were told [Lanza] had around 500 people on this sheet,” a law enforcement veteran told the newspaper. “Names and the number of people killed and the weapons that were used, even the precise make and model of the weapons. It had to have taken years. It sounded like a doctoral thesis, that was the quality of the research.”

Twenty children and six adults were killed at the school on Dec. 14 by Lanza, who also killed his mother, Nancy Lanza, before taking his own life as police responded to the school. It has previously been reported that law enforcement officials found research about previous mass murderers at the Newtown, Conn., Lanza shared with his mother, but the extent of that research was not explicitly clear.

A law enforcement veteran who attended the International Association of Police Chiefs and Colonels mid-year meeting in New Orleans last week — a conference where state police colonels share information — told columnist Mike Lupica that gunmen like Lanza should be referred to as “glory killers” instead of mass murderers.

“They don’t believe this was just a spreadsheet. They believe it was a score sheet,” the unidentified career cop told Lupica. “This was the work of a video gamer, and that it was his intent to put his own name at the very top of that list. They believe that he picked an elementary school because he felt it was a point of least resistance, where he could rack up the greatest number of kills. That’s what (the Connecticut police) believe.”

Investigators also believe Lanza was determined not to be killed by responding officers, according to the unidentified officer.

“They believe that [Lanza] believed that it was the way to pick up the easiest points,” he continued. “It’s why he didn’t want to be killed by law enforcement. In the code of a gamer, even a deranged gamer like this little bastard, if somebody else kills you, they get your points. They believe that’s why he killed himself.

“They have pictures from two years before, with the guy all strapped with weapons, posing with a pistol to his head,” the officer continued. “That’s the thing you have to understand: He had this laid out for years before.”

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