It’s only dumb luck, rather than laws, that prevents more mass shootings:

A day before a gunman in Oregon killed eight classmates and his college writing teacher, Tuolumne County sheriff’s detectives foiled a plot by students to go on a shooting rampage at their high school near Yosemite National Park, authorities said.

The Summerville Union High School students, all male, had detailed plans that “included names of would-be victims, locations, methods in which the plan was to be carried out,” Sheriff Jim Mele told reporters at a news conference Saturday. The targets included other students and faculty members.

The boys confessed, Mele said, according to the Modesto Bee and KCRA-TV Channel 3. Three were arrested Wednesday and a fourth detained Friday on suspicion of conspiracy to commit assault with deadly weapons, a statement provided by the sheriff’s office said.

“They were going to come on campus and shoot and kill as many people as possible at the campus,” Mele told the Bee.

The suspects were overheard by other students talking about their plans. Detectives later found evidence that the suspects planned to act during an upcoming campus event, the news organizations reported.

“Students noticed suspicious activity, and … they felt uneasy enough to go to staff,” the sheriff said in televised remarks.

The names of the suspects were not released because they are juveniles.

No weapons were found by detectives, but the students were planning to obtain them, the news organizations reported. No specific motive was disclosed.

The high school serves students in Tuolumne, about three hours east of San Francisco.