Three words scream out from a storybook 10-year-old Adam Lanza wrote as a fifth-grader.

"Let's hurt children."

The young Lanza put those words in the mouth of Dora the Beserker (sic), one of the homicidal characters included in "The Big Book of Granny," which chronicles the evil adventures of gun-toting Granny and her son.

The violent and chillingly prophetic story was a central part of the background investigation into Adam Lanza's life, traced up until he committed the massacre at Sandy Hook Elementary School. Lanza and another boy wrote the book as a class assignment but it was never handed in, investigators said.

The book is included in the summary of the 11-month state police investigation released Monday by Danbury State's Attorney Stephen J. Sedensky III.

The eight chapters of Lanza's book take Granny and her son through a litany of dark episodes as they tote a bag carrying a handgun, an M-16, and a shotgun, firearms eerily similar to those he would use years later at the Sandy Hook school. Granny robs a bank with a bullet-spewing cane. She guns down soldiers at a Marine boot camp and travels back in time and murders The Beatles. She threatens to shoot and kill children in a classroom.

And often, the violence is between Granny and her son.

Granny kicks the boy into a burning fireplace, punches him in the face and shoots at him. After the bank robbery, the son shoots Granny in the head with a shotgun.

A decade later, 20-year-old Adam Lanza would shoot his mother in the head before driving to Sandy Hook Elementary where he would commit one of the worst school shootings in American history.

In one chapter, Dora the Beserker enters a day-care center with Granny and her son as another character tries to distract the children.

"Let's hurt children," Dora then suggests, according to a summary of the book written by a state police detective assigned to read the spiral-bound booklet.

Although he never acted them out until Dec. 14, Lanza appeared to hold onto many of these violent themes throughout his life, Sedensky wrote in his report.

Sedensky said Lanza had contributed posts to an Internet blog focused on mass shootings, including the murders at Columbine High School. The teenager exchanged emails with people who shared similar interests.

The Courant reported in July, citing an investigative source, that Lanza meticulously edited online accounts of mass murders throughout the world, and participated in chats on firearms sites and violent, first-person video-gaming forums, posting as "Kaynbred.''

Inside the Lanza home, Sedensky said investigators found a spreadsheet with information about mass murders, books and news articles about killing sprees and a computer game titled "School Shooting" in which a player controls a character who shoots students in classrooms.

Lanza spent a good deal of time online playing graphically violent, first-person video games, as well as decidedly non-violent games, the report states.

"The shooter liked to play a music-video game called 'Dance Dance Revolution,' and spent hours in the lobby arcade of a local theater, playing the game, Sedensky said.

Lanza's enigmatic shadow looms over Sedensky's report. The prosecutor writes that those who knew Lanza described the shooter "in contradictory ways.''

He notes that Lanza displayed "a fascination with mass shootings and firearms," yet was never violent himself – until the rampage. Some recalled that Lanza could be humorous; others found him emotionally distant, rigid, and lacking empathy.

He was capable of "laughing, smiling, and making jokes, though always in a dry fashion,'' a friend told investigators. He wrote about mass murder, but also about human nature, morality, empathy, hiking, and cookies,'' the report states.