MARYSVILLE, Wash. -- Investigators say a 58-year-old woman whose body was found along Interstate 5 early Wednesday morning appears to have been struck by a vehicle while she was walking, and the driver remains at large.

Jim Floyd and his wife were driving to work about 6:40 a.m. when he spotted the body next to the southbound lanes near the 116th Street exit.

"We backed up and sure enough there was this lady laying there in the ditch face down," he said.

Snohomish County Sheriff spokeswoman Rebecca Hover said the woman appears to have been walking along 34th Avenue Northwest near the interstate when she was hit. Investigators believe the crash occurred sometime between 4:35 a.m. and 6:35 a.m.

The impact knocked the woman out of her shoes and over a wire fence.

"We don't know what type of vehicle struck her, but we are hoping that the public can help us either by telling us who this woman is or by telling us what happened here," Hover said.

Detectives recovered a motorcycle and gas can that were found at the scene, but Hover said it was not clear if either were related to the crash.

Deputies cordoned off the area while they collected evidence, but traffic on I-5 was not blocked.

"It makes me sick to my stomach because somebody's out there that hit somebody and she might have been laying there for a long time," said Cyndi Cullison.

Anyone with information is asked to call the sheriff's office at 425-388-3845.