POWAY, Calif. -- Friends of a Poway High School graduate held a candlelight vigil in her memory Sunday, as officials investigate why she was found floating facedown and lifeless in the San Luis Rey River at a remote campground near Palomar Mountain.

Jaymie Rose Darrow, 19, was found in the river along state Route 76 east of Pauma Valley at about 7:15 p.m. Saturday, said a San Diego County Medical Examiner's Office investigator sheriff's Lt. Anthony Ray.

Her hometown was listed by Ray as Santa Barbara, but Web pages on a social networking site indicate she is a Poway High graduate and current student at UC Santa Barbara.

No signs of foul play were apparent, he said.

The incident happened at a campground operated by the La Jolla Band of Luiseno Indians, where inner tubing on the San Luis Rey River is a popular diversion. The campground is east of the junction of State Route 76 and the South Grade Road up Palomar Mountain.

The San Diego County Medical Examiner's Office is investigating the death in conjunction with the U.S. Bureau of Indian Affairs, as the campground is on the La Jolla Indian Reservation. An autopsy is scheduled for later Sunday.

Her mourning friends announced the vigil on the Internet Sunday.