"I think it's really scary for women especially who have children," said Melissa Baxter who uses the trail.
The trail, just off Missouri Flat Road, is where investigators said the suspect approached the woman Friday afternoon.
The El Dorado County Sheriff's Office said the suspect first asked the woman about the location of a business then asked her for a dollar, which she gave him.
"Then she went to shake his hand for him saying thank you he pulled her in and sexually assaulted her with the other hand," said Sgt. Tasha Thompson with the El Dorado County Sheriff's Office.
The victim fought back. The man apologized and ran away, but he left his red Nike shoe behind. It's what investigators will use for a possible DNA match.
"We're just hoping someone in the community recognizes that shoe with the description of the subject," Thompson said.
The suspect is described as a 14 to 20-year-old Hispanic male with dark skin and dark messy hair. He's about 5 feet 7 inches tall.
Contact El Dorado County Sheriff's Office with information.