The teenager accused of gunning down two employees inside a New Mexico public library had planned to shoot up his high school but went to the library instead, according to court documents filed Wednesday.
The 16-year-old told police he did not know why he picked the Clovis-Carver Public Library and that he did not know anyone there, the documents said.
But he told investigators he had wanted to target his high school for a long time because he was "mad at everyone since he got kicked out of school last year," the documents said. He also told them he felt like no one liked him.
The teen was on a two-day suspension from Clovis High School on Monday, the day of the shooting. The teen's pastor, David Stevens, has said the suspect had fought back after another boy hit him.
NBC News generally does not identify juveniles accused of crimes.
The suspect is accused of taking two handguns from his father's safe and walked into the library in the rural community on Monday afternoon. He told investigators he first used the library's bathroom, exited and started shooting and yelling.
Witnesses have said it appeared the gunman fired randomly as parents, children and others hid under tables and behind closed doors. Four others also were seriously wounded, including a 10-year-old boy.
The sophomore faces nearly a dozen charges — including first-degree murder, child abuse, assault with intent to commit a violent felony and aggravated battery.
Authorities plan to file a motion requesting the case's transfer from the juvenile system to adult court. The boy was in custody Wednesday at a juvenile detention center pending a hearing Thursday afternoon.
The boy's father called police Monday to report that the guns had been taken from the safe and that his son was not home but the shooting had already happened, the court documents said.
The teen told investigators that he had "been thinking bad things for a while" but did not want to tell his family, his girlfriend or friends at the Living Word Church of God, where he had been attending services for about three months, the documents said.
Stevens, the youth's pastor, said the teen had been troubled but appeared to be turning his life around, never missed a service and recently helped the congregation raise money for a youth camp. The boy and Stevens' daughter were dating.
Investigators found a bag with suicide notes inside a desk drawer at the teen's home, the documents said.
After officers stormed the library and the teen surrendered, police found a handgun on a nearby shelf as the teen held his hands above his head, the documents said. They also found a bag in the library with a second handgun and ammunition.
The two workers killed were circulation assistant Wanda Walters, 61, and youth services librarian Kristina Carter, 48.
Another circulation assistant, Jessica Thron, 30, was injured and authorities identified the wounded library patrons as 10-year Noah Molina, his 20-year-old sister Alexis Molina and 53-year-old Howard Jones.
They were being treated at University Medical Center in Texas, across the state line from Clovis.
The boy's parents said in a statement Wednesday they were saddened by the shooting and offered their thoughts and prayers to the victims and their families.
"As parents, this is something you never expect. Nathaniel is a loving son to us, a wonderful brother to his siblings and a caring member of our family," the statement said.
Clovis residents continued to place flowers and ribbons on makeshift memorials for the victims. Vigils were planned for Wednesday and Thursday.