SPOKANE, Wash. -- Guns, ammunition, a Molotov cocktail and a school yearbook with pictures of faces marked with X's were seized by police from the home of a Washington state high school sophomore accused of, according to court documents filed in the case.
Investigators last week also found a "manifesto" in the home of 15-year-old Caleb Sharpe, said the documents made public Friday that emerged in the media Monday -- as students returned to Freeman High School for the first time since last week's shooting.
The documents did not provide details about what was written in the manifesto discovered in a notebook. Another notebook had a list of chemicals. The Molotov cocktail was described as a "practice" incendiary device, but the documents provided no more details.
The school, near the small town of Rockford near Washington state's border with Idaho, was closed Thursday and Friday after authorities said Sharpe brought a handgun and an assault rifle to school Wednesday in a duffel bag he had carried onto his high school bus.
The assault rifle jammed when he tried to load it inside the school. He took out the pistol, and that's when he was confronted by victim Sam Strahan, who told him something to the effect of, "I always knew you were going to shoot up the school" and "You know that is going to get you in trouble."
Sharpe allegedly shot Strahan in the abdomen, and when the boy bent over, he shot him again in the face, the documents say. Strahan was later pronounced dead.
Witnesses described a panicked scene when shots rang out, with bullets hitting the ceiling and students screaming and running down the hallway. The documents say Sharpe then fired down the hallway, wounding three other students.
Sharpe told police that he had beenbut did not target him specifically. He also said he didn't target the three victims who were wounded.
"Instead, he'd come to the school to teach everyone a lesson about what happens when you bully others," police documents say.
Court documents released Tuesday revealed that Sharpe entered the plea Friday during a brief court appearance two days after the shooting.
Some students walked arm-in-arm as they showed up for their classes on Monday.
There was a counselor present in every classroom and retired teachers also showed up to offer support and help. Many parents accompanied their children to school at the urging of Randy Russell, the school district's superintendent.
The Spokesman-Review newspaper reported over the weekend that Sharpe had been suspended for bringing threatening notes to school and that the shooting happened on the first day he had returned.
Russell told the newspaper that the district followed protocol by suspending the student and sending him for a mental evaluation.
Sharpe faces a charge of first-degree murder, and might be tried as an adult.
Documents and his classmates said Sharpe brought notes to school about doing "something stupid" and was obsessed with past school shootings.
CBS News' Mireya Villareal reports Sharpe recorded a series of disturbing YouTube videos, which appear to show the teen firing guns. In one, the suspect and a friend display several guns, including what appear to be airsoft weapons and one actual rifle, and act out a scenario where they search for an imaginary neighborhood drug dealer.
In one video, Sharpe pretends to shoot a friend before going inside to play a video game, Villarreal reports. Classmates told local media they knew he had an assault rifle because of the videos.
Sharpe also had been meeting with a school counselor because of suicidal thoughts and left a suicide note at home for his parents before the shooting, an investigator for the Spokane County Sheriff's Office wrote in an affidavit.
Sharpe has been in custody since the shootings and faces a Sept. 26 court appearance.
His family last week issued a statement expressing condolences and asking for prayers for the victims and their relatives.
The Associated Press doesn't typically name juvenile suspects but is doing so because of the severity of the accusations and because Sharpe's name was released in public documents.