Report: Sandy Hook Shooter Adam Lanza Was Obsessed With Mass Shootings

Sandy Hook Elementary School shooter suffered from mental illness, got little help.

Adam Lanza's Western Connecticut State University ID photo, right, and an aerial image of his mother's home in Newtown, Conn., where he lived, were among the files released Monday, Nov. 25, 2013, relating to the Sandy Hook shooting.
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After nearly a year, families in Newtown, Conn., still do not know why Adam Lanza killed 20 first graders and six adults at Sandy Hook Elementary School before turning a gun on himself.

They may never know.

[READ: Newtown Residents Vote to Rebuild Sandy Hook]

A new report released Monday paints a disturbing portrait of a lone gunman suffering from serious mental illness. The Connecticut State Police report, however, provides few clues as to what motivated the 20-year-old shooter.

"Despite the collection of extensive background information on the shooter through a multitude of interviews and other sources, the evidence clearly shows that the shooter planned his actions, including the taking of his own life; but there is no clear indication why he did so or why he targeted Sandy Hook Elementary School," the report said.

On the morning of Dec. 14, 2012, carrying more than 30 pounds of weapons and ammunition, Lanza shot his way into Sandy Hook Elementary school. He killed the principal, Dawn Hochsprung, and school psychologist, Mary Sherlach, in the school's north hallway before entering two different classrooms. He killed 20 children and their teachers with a Bushmaster rifle, a semi-automatic weapon that fired 154 bullets in five minutes.

Lanza struggled with mental illness, a history of obsessive-compulsive behaviors and a fascination with mass shootings - particularly the 1999 school shooting in Columbine, Colo., the report said. Yet, none of the mental health specialists he had a record of meeting with predicted he was capable of lashing out violently. While Lanza had seen professionals for his mental issues, but declined medicines prescribed to help him manage his symptoms.

"The shooter refused to take suggested medication and did not engage in suggested behavior therapies," the report said.

[PHOTOS: Sandy Hook Elementary Students Return to Class]

Lanza avoided crowds, despised loud noises and was particular about the way his food was prepared and placed on his plate. He barred anyone from entering his room and disliked his mother's cat so strongly she was forced to get rid of it.

"The shooter disliked birthdays, Christmas and holidays. He would not allow his mother to put up a Christmas tree," the report said.

In order to cope with her son's ticks, Nancy Lanza, quit her job to attend to him full time. She was planning on moving to either Washington, D.C., or North Carolina with her son so he could attend school or work as a computer technician. In the days before the shooting, Lanza had been left at home alone while his mother traveled to New Hampshire. 

By December 2012, Lanza was spending most of his time inside his home. His mother told friends she was "concerned about him."

In the aftermath of the shooting, reports of Lanza's violent video game playing were pervasive. Yet, the report indicates Lanza also filled his time playing an assortment of other games, including Dance Dance Revolution and Super Mario Brothers. He assembled computers and wrote poetry. He often reformatted his computer so his searches were less traceable because he was committed to "staying off the grid."

[READ: Newtown Victim's Parents Met With Adam Lanza's Father]

One of the only indications that Lanza had considered acting violently, according to the report, came in fifth grade, when he wrote a short story featuring a woman who has a gun in her cane and shoots people.

For the families of Sandy Hook Elementary School, the report was yet another blow, thrusting the tragic shooting back into the headlines.

Donna Soto, who lost her daughter, Victoria, in the shooting, said the report dredged up emotions, but offered few answers.

"How can we live without Vicki? How do we celebrate Christmas without Vicki? How do we go on every day missing a piece of our family?" she said on Facebook, according to a report in USA Today.

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