NEWTOWN, Conn. (USA TODAY) - Gunman Adam Lanza acted alone and didn't conspire with anyone when he killed his mother, Nancy, in their Sandy Hook home Dec. 14 and then slaughtered 26 children and educators at Sandy Hook Elementary School, a Connecticut State Police report released Monday says.
Investigators reported that a review of electronic evidence and digital media that "appeared to belong to the shooter'' showed he had a preoccupation with mass shootings, particularly the Columbine High School shootings in Littleton, Colo., in 1999.
The summary report by the lead investigator, State's Attorney Stephen Sedensky III, says Lanza shot his way into the school and first killed Principal Dawn Hochsprung and school psychologist Mary Sherlach in the north hallway.
Lanza also shot two other staff members in the hallway who survived.
He then went into two classrooms and killed 20 children and four teachers.
Lanza, 20, used a Bushmaster XM15-E2S rifle to kill the victims at Sandy Hook school before killing himself there with a Glock 10mm handgun. He killed his mother in her bed with a .22-caliber rifle.
The Connecticut State Police's full evidence file about the shootings, which may total thousands of pages, was not released Monday.
The summary report said someone near the Lanza's Sandy Hook home heard two or three gunshots between 8 a.m. and 9 a.m. on Dec. 14. The person thought the shots were from hunters, though they sounded ''unusually close,'' the report says.
Police later found Nancy Lanza dead in her bed, and the rifle used to kill her was on the floor next to the bed.
The report details the actions of Adam Lanza when he arrived at Sandy Hook school. He parked his 2010 Honda Civic next to a No Parking zone outside the school and approached the front entrance just after 9:30 a.m. He was armed with the Bushmaster XM 15-E2S rifle, a Glock 10 mm handgun, a Sig Sauer 9 mm pistol and a large supply of ammunition.
Finding the school doors locked, Lanza shot his way into the building through the plate glass window to the right of the front lobby doors.
The school's main office staff reported glass breaking at about 9:35 a.m. and saw the shooter, "a white male with a hat and sunglasses," carrying a rifle, the report says.
"The shooter walked normally, did not say anything and appeared to be breathing normally," the report says.
Police found numerous violent video games in the basement of the Lanza home.
"The vast majority" of people who knew Lanza and were interviewed by police said they had no explanation for the shooter's actions, the report says.
The autopsy performed on Nancy Lanza determined that the cause of death was multiple gunshots to the head, the report says. An autopsy of Adam Lanza on the same day revealed that Lanza was 6 feet tall and weighed 112 pounds. No drugs were found in his system.
One month before the shooting, Nancy Lanza sought to buy her son another computer or parts for a computer to build himself, the report said. She was concerned about him and said he hadn't gone anywhere in three months.
She said he would communicate with her only by e-mail, although they lived in the same house. She never expressed fear of Adam or concern about her safety, the report said.
She planned to sell her Newtown home and move to Washington state or North Carolina so her son could go to a special school or get a computer job, the report said. She planned to buy a recreational vehicle where Adam could sleep while the house was being shown to prospective buyers because Adam would not sleep in a hotel, the report says. He refused to leave the home and go to a hotel when the home lost power during Hurricane Sandy in October 2012.
In November 2012, Nancy Lanza wanted to buy her son a CZ 83 pistol for Christmas and prepared a check for that purpose.
At about 5:30 a.m. on Dec. 10, four days before the shootings, Nancy told a friend that Adam had "bumped his head badly," the report says. There was some bleeding, but "he was okay."
Nancy left for a trip to New Hampshire and cooked Adam's favorite food before she left. She went to New Hampshire without him and returned Dec. 13 at about 10 p.m., the night before she was killed.
While Nancy Lanza was away, a GPS device in the Lanza home showed that a trip was made between 2:09 p.m. and 2:32 p.m. on Dec. 13, the day before the shootings. The trip was made to and from the "Sandy Hook area" from the Lanza house and was presumable made by the shooter in his black Honda Civic, the report says.
Investigators conducted many interviews with people who knew Adam and his family. No evidence, the report says, suggests that Adam had a reason to target Sandy Hook Elementary School, which he had attended as a boy.
"As best can be determined, the shooter had no prior contact with anyone" who was in the school during the day of the shootings, the report says.
Adam, it says, appears to have had "no continuing involvement" with the school after he went there as a youth.
People who knew Adam describe him "in contradictory ways," the report says. "He was undoubtedly afflicted with mental health problems," the report says. "Yet, despite a fascination with mass shootings and firearms, he displayed no aggressive or threatening tendencies."
The report says that, "in some contexts," Adam was viewed as having "above-average intelligence," and, in other contexts, below-average intelligence.
Some people said he had been bullied, but others, including many teachers, said he wasn't bullied.
His mother, Nancy, and his father, Peter Lanza, who were divorced, said Adam was bullied growing up, the report says. Peter said the bullying was not excessive and concnerned Adam's social awkwardness and physical gait.
USA TODAY interviewed four classmates after the shootings, and all said students did not bully him.
The report says Adam "appears to have had few friends growing up."
Adam's father, Peter, saw him regularly until he was 18, the report said. They went hiking and played video games, and went shooting twice. Adam had a cell phone but never used it. His father had to contact him by e-mail.
Adam's relationship with Peter deteriorated in the fourth quarter of 2010, the last time the two saw one another. Prior to December 2012, Adam stopped responding to his father's mail and e-mails about getting together, the report says.
One witness said Adam did not have an emotional connection with his mother. When Nancy Lanza asked him if he would feel bad if anything happened to her, Adam replied, '"No,'" the witness said, according to the report.
Other witnesses, though, said Adam was close to his mother, and she was the only person he would talk to.
A person who knew Adam in 2011 and 2012 said Adam described his relationship with Nancy as strained because Adam thought her behavior was not rational.
The report says Adam often changed clothing during the day, and his mother did his laundry daily. She was not allowed in Adam's room, even to clean, the report says. No one was allowed in the room, it says.
Adam disliked birthdays, Christmas and holidays, the report says. He didn't allow his mother to put up a Christmas tree. Nancy Lanza explained this by saying Adam had no emotions or feelings, the report says.
Shooting was a family pastime, and Adam enjoyed shooting and going to a target range with his mother and brother, the report says. Adam and his mother took a National Rifle Association safety course.
Adam played video games often, both solo and online, the report says. He played violent and non-violent games and his favorite at one point was Super Mario Brothers.
An acquaintance who played a music and dance video game called Dance Dance Revolution with him in 2011 and 2012 said Adam never mentioned being bullied growing up. The acquaintance said Adam enjoyed nature and hiking and sometimes laughed, smiled and made dry jokes.
The report says the final shot at Sandy Hook school was fired 63 seconds after the first Newtown Police Department officer arrived at the school. About five minutes later, Newtown Police officers entered the school.
This is the timeline: The first 911 call to the Newtown Police Department was received at 9:35:39 on Dec. 14. At 9:36:06, a police department dispatcher broadcasted that there had been a shooting at Sandy Hook school. The first Newtown police officer arrived at the school at 9:39:00, and two others officers arrived at 9:39:13. Gunshots were heard. At 9:39:34, a police office encountered an "unknown male" running along the east side of the school. At 9:40:03, the last gunshot was heard. The shot is believed to be the one used by Lanza to commit suicide. At 9:44:47, Newtown police officers entered the school.
The report says that from the time a Newtown Police officer encountered an unknown male running outside the school at 9:39:34 until after staff and children were evacuated from the school, "all responding law enforcement officers operated under the belief that there may have been more than one shooter and acted accordingly."
Adam Lanza attended Sandy Hook Elementary Schoolfrom 1998 to 2003, first through fifth grades, the report said. He was not assigned to the two classrooms where the shootings occurred.
He attended Newtown High School and graduated in 2009. He took classes at Western Connecticut State University after high school.
Besides shooting and killing Hochsprung and Sherlach in the school's hallway, two other staff members were shot and wounded in the hallway. One of the wounded staff members was shot in a leg and then shot again when on the floor. The staff member crawled back into the conference room and shut the door. The other staff member was further down the hallway and struck in the foot with a bullet. The wounded staff member then retreated into a classroom.
After killing the two educators and wounding two others in the hallway, Adam Lanza went into the school's main office. Staff mebers there were hiding, and Lanza exited the office.
Lanza went to first-grade classrooms numbered 8 and 10, where he killed 20 children and four adults with the Bushmaster rifle. Twelve children survived, one from classroom 8 and 11 from classroom 10.
Lanza killed himself in classroom 10 with one gunshot to the head.
Classroom 8's substitute teacher that day was Lauren Rousseay, 30, and she was assisted by Rachel D'Avino, 29, a behavioral therapist. They and 15 children were killed in that classroom.
Classroom 10's teacher was Victoria Soto, 27. Working with her was behaviroal therapist Anne Marie Murphy, 51. Both were e killed. Five children were found, with Murphy partially covering one child. Four of the five children were dead. The fifth child was taken to Danbury Hospital and pronounced dead. Nine children ran out of the room and survived. A police officer found two uninjured children in the class bathroom.
With the release of the summary report, "the investigation is closed, and no additional release of information or documents by this office is anticipated," Sedensky said in a written statement Monday.
He didn't release recordings of 911 emergency calls made on Dec. 14. Their release was recommended by a state Freedom of Information Commission in September, but Sedensky, in an attempt to protect victims' families, has gone to court to stop the release.
The Dec. 14 shootings shattered the small, close-knit western Connecticut community and raised several national issues. President Obama went to Newtown on Dec. 16 to comfort families who lost loved ones, then pushed for new gun-control laws. Proposed legislation was not passed by Congress, but Connecticut and some other states implemented stricter gun laws.
The shootings also prompted many communities to take steps to make schools more secure and began debates about the effectiveness of the nation's mental health system.
Release of the summary report followed a months-long debate among Connecticut officials, news outlets, open-government advocates and others over the public's right to know and the pain such a report could inflict on families who lost relatives in the shootings.