A series of videos uploaded on YouTube showed the teen shooter involved in the Spokane school shooting on Wednesday brandishing guns and simulating a mock shootout with a friend.

Classmates and witnesses identified the accused as the perpetrator of the attack at Freeman High School near Spokane, Washington, which killed one of his classmates and injured three others. He was taken into custody by Spokane County police and was put in a juvenile detention center, reports said.

In the videos put up by a channel belonging to the juvenile, the accused and his friend were seen running with toy guns and shooting at each other, with sound effects added to make the gun shots seem real. Uploaded in May on the channel Mongo Walker, the video called “J-Baumb kills Mongo” was taken off the site Wednesday but was put up again by other channels, Heavy.com reported.

Another video titled “The Second Round:” was uploaded in June in which the juvenile’s friend is seen pretending to be bleeding on the ground. Later they act out a sequence where the juvenile hands out an Airsoft pistol to the friend to take out a fictitious drug dealer in their neighborhood. 

The Spokesman-Review reported that while many of the earlier videos on the channel seemed commonplace, like one in which he pretends to be Bear Grylls, the British reality TV star, recent ones showed him playing with guns and engaging in violent activities. At least one of the guns in the videos appears to be a real rifle, the report said. 

Associated Press quoted one of his friends, Michael Harper, saying the accused had written notes to friends towards the beginning of the school year in which he indicated he planned to do “something stupid” and might get killed or jailed.  The school counselor was also alerted about the notes, Harper said, but the response of the school authorities was not clear.

Harper also described the accused as “nice and funny and weird” and a big fan of the TV show “Breaking Bad.”

“He was really funny, and he likes to make lots of jokes,” another friend Liam Marshall said. “He just lost his father this past summer. I thought he was a lot wiser (after his father died). He didn’t do stuff like he used to do. But, he was still funny.”

He added that the juvenile was obsessed with other school shooting incidents.

His YouTube videos were well-known in his friend circles. “We knew he had an assault rifle, because he uses it in his YouTube videos,” said Paul Fricke, a junior, to the Spokesman-Review.

According to Spokane County Sheriff Ozzie Knezovich, the shooter’s possible motivation was he being bullied by school mates, reported Los Angeles Times.

Describing the attack, Knezovich said the shooter brought multiple weapons to the campus and tried to fire one gun among them, which jammed. He then pulled out a second one and fired a fatal shot at a student trying to stop him. Moving down the school hallway from there, he fired and struck three other students.

Governor Jay Inslee said in a statement that “all Washingtonians are thinking of the victims and their families, and are grateful for the service of school staff and first responders working to keep our students safe”.