Investigators acting on a tip unraveled a plot to carry out a mass shooting at a suburban Los Angeles high school, arresting a pair of students who planned to target three school staffers and kill as many people as possible, police said today. School officials learned of the plot on Thursday and notified detectives, who began watching the 16- and 17-year-old boys and monitoring their online activity, said South Pasadena Police Chief Arthur Miller. The pair didn't have a date for an attack or weapons, but their online messaging included the names of three staffers to target and threats to randomly kill students, Miller said.
They were also researching automatic firearms, handguns, knives, explosives, and tactical techniques, he said. "Three or four days' worth of surveillance on the Internet indicated that they had a very real threat," he said. "They had a plan in mind that they were going to execute." The names of the teens have not been released because of their ages. Classes start again Thursday in the quaint San Gabriel Valley suburb known for its quality schools and community involvement in education. Police plan to have a larger presence than usual on campus for the first day of school. (Read more Los Angeles stories.)