Two US teenagers arrested on charges of plotting a high-school mass shooting had a "very methodical" plan and wanted to die in the gun battle, police said Tuesday.
The 16- and 17-year-olds, who police did not identify, wanted to kill as many people as possible and "planned to die through a shootout with the police," said Arthur Miller, the police chief in the Los Angeles suburb of South Pasadena.
The plot to kill three staff members and as many students as possible at South Pasadena High School, which has 4,500 students, was "very methodical and it seemed very viable," said Miller.
Miller, who gave few details of the plot, said the pair had a "chilling" demeanor and displayed no emotion when interrogated.
Two high-school members alerted authorities, who monitored the suspects' social media behavior. After they accumulated compelling evidence, police obtained a search warrant and went to their homes.
Police did not find weapons, but did learn by looking at their computers that the teenagers were researching how to make explosives, and there was a possibility of obtaining an automatic weapon, Miller said.
The parents cooperated with police, and both teens -- neither of whom had a criminal record -- were arrested on charges of conspiracy and making credible threats.
Police said in a statement that one of the students was arrested without incident while the other resisted and tried to flee.
There was no date set for the shooting spree, and Miller said the plot was still in the planning stage.
FBI agents will help in the probe, Miller said.
The new school year starts on Thursday in Los Angeles and students outside the school expressed concern over the apparent plot.
"I feel a lot more suspicious that someone could still be working on that plan," 16-year-old Malika Palacio told AFP.
Samuel Garcia, 17, said he trusted school security and was glad that they were arrested, but his mother Cindy was not as sanguine. "That's terrifying," she said.
"To think I could have died in two days," said 14-year-old Bethany, who did not give her last name.
She said that she did not know the suspects, but wondered if they were victims of bullying. "There must have been something bad to make them want to have this plan," she told AFP.