LAKE ISABELLA, Calif. -- Rumors about a murder and serial rapist are flying around the Kern River Valley and beyond, but authorities say they not true.

"There's one sexual assault investigation that has occurred here in the Lake Isabella area," Kern County Sheriff Senior Deputy Scott Lopez said Monday. "It is an ongoing investigation."

He said the sexual assault happened about two weeks ago, but rumors have circulated about a number of rapes and even murders.

Confirmation that there's even one sexual assault worries Cerro Coso College student Hollie McMartin, she said.

"Rape is horrible," McMartin said. "People don't deserve to go through it, and if they're not telling anybody about it, how do you know to protect ourselves?"

Lopez said there was very little information to put out on the sexual assault.

"We could put out information, but it would be very very vague," he said. "It's an isolated incident."

Sandra Hart-Weser is one of the people who had heard rumors of several assaults.

"I heard there were a couple rapes, and there was one that had her neck trashed," she said.

Students huddled outside the Cerro Coso campus Monday and said they had seen warning posters up in the school halls on Friday. Alex Jacobs said the posters warned students to walk in pairs and to be cautious.

Jacobs was also not set at ease in knowing that there had been only one sexual assault.

"No, because there's still one (suspect) out there," she said.

The serial rapist rumors had been circulating on social networking Web sites and include a photo of the accused rapist.

"I've seen the photo if it," Lopez, the sheriff's investigator, said, "and it doesn't match the description given by the victim in my investigation."

Sheriff's officials said they don't have any evidence to support the claim that there's a serial rapist on the loose, and they don't know the origin of the photo or the identity of the person in the photo.

Another rumor running rampant is that a young woman was sexually assaulted, murdered and dumped into the Borel Canal.

"That is totally unfounded," Lopez said.

Some women had heard the victim who was assaulted had been walking down Erskine Creek Road toward the shopping center on Lake Isabella Boulevard. Since it's right next to the college campus, that had many students on edge.

Hart-Weser said she worries for students at the college and nearby schools, and she just wants information.

"I'd like them to let the community know what's going on," she said.

Anyone with information helpful to any of these investigations is asked to call Lopez at (760) 549-2100.