Monday at Incredible Kids Preschool and Daycare in Cameron Park, there were no kids. Instead, a "closed" sign hung on the door as the owners changed the locks.
The school's owner, Dave Olson, tells FOX40 they received two threatening voicemail messages in the past four days.
"They were graphic, they were threatening the teachers mostly," Olson said.
He said the messages threatened to kill and rape staff and children.
"I have to take it seriously in today's age there's a lot of nuts out there," Olson said..
The El Dorado County Sheriff's Office said several area preschools and businesses have received similar voicemails from a male caller.
"Just shocking. Shocking that there's an individual out there that is sick," said Lisa Hayes, owner of Ms. Lisa's Montessori in Cameron Park.
Hayes says she got an alarming message early Friday morning, but decided to stay open Monday and let parents decide whether to bring their children in.
"We're just saddened that this is what life in society has come to. That people cannot drop their kids off at school whether it be preschool, elementary school, high school, and go to work and not have to worry," Hayes said.
Concerned about the threats, Hayes is keeping the doors locked. But she's comforted knowing the sheriff's department has increased patrols as they try to track down whoever is responsible for the disturbing voicemails.
Schools were never ordered to go on lockdown.
The El Dorado county sheriff's office says there is no credible threat, but anyone with information is asked to call them.
Stay with FOX40 and FOX40.com for the latest information as this story develops.