"It's not unusual to have a school shooting somewhere in the country and then have copycats that might not even be on that campus, but saying they're going to come do something like that," Sacramento Police Chief Daniel Hahn said.
The latest cause for concern was a rumor of a planned shooting Tuesday at C.K. McClatchy High School during fifth period.
"A parent said that her student had a threat to shoot up the school and it just blew up on social media," McClatchy junior Lauren Pratt said.
Police investigated the threat and in a statement released later Tuesday said they have "no reason to believe that the alleged threat is credible."
"We have not found anything that an actual student in question has said any of those things or threatened to come on campus," Hahn said. "They're all at this point, we still have some people to talk to, but at this point, it looks like a rumor that kind of got bigger."
Rumor or not, Pratt said a lot of her peers didn't come to class on Tuesday, along with some teachers.
"Nobody's in school. There's been about like nine people in each class and everybody's really, really scared," she said. "Even though they say it's not going to happen, I'm still pretty scared that it blew up this much overnight."
In the meantime, police are trying to ease concerns and use the panic as a reminder about using social media responsibly.
There was also a police presence at McClatchy on Tuesday, helping parents and students feel safer.
"In light of recent events across the country, an increased police presence will be around our schools for the next several days," Monday's statement read.