SAN DIEGO – Chelsea King is a straight-A student who plays French horn for the San Diego Youth Symphony, runs on the school cross-country team and actively volunteers in a peer counseling program.
At Poway High School, photos adorn the walls with the caption, "Last seen 2-25 at RB Community Park wearing running clothes."
The 17-year-old's family and authorities are holding out hope she will return safely. Thousands of volunteers have helped search for the teen since she disappeared Thursday, and her father, Brent King, told CBS' "The Early Show" Tuesday, "Until I hear differently, I believe she's alive."
But as optimistic searchers spread out over the popular area for trail runners, police were determining whether to charge a registered sex offender who was arrested Sunday for investigation of the teen's murder and rape.
John Gardner III, 30, remained in custody without bail after his arrest outside a Mexican restaurant in suburban Escondido on Sunday. Steve Walker, a spokesman for the San Diego County district attorney's office, said a decision would be made by Wednesday about filing charges.
Gardner, of Lake Elsinore, pleaded guilty in May 2000 to molesting a 13-year-old female neighbor and was sentenced to six years in prison. Prosecutors say he lured the victim to his home with an offer to watch "Patch Adams," a 1998 movie starring Robin Williams.
Sheriff Bill Gore told ABC's "Good Morning America" on Monday that the questioning of Gardner hadn't produced any leads. Sheriff's spokeswoman Jan Caldwell declined to say if searches of Gardner's home and his mother's San Diego home yielded evidence.
Brent King pleaded for anyone with information about Gardner to come forward. Investigators suspect Gardner could be tied to a Dec. 27 assault on a female jogger from Colorado who fended off her attacker in the same park.
"Anybody who knows anything about the person they have in custody — whatever you want to call him, I can't even put a word to it — please let us know," he said.
In an interview Monday, the Kings, who also have a 13-year-old son, recounted their daughter's disappearance.
Brent, 47, returned from the gym around 5:30 p.m. Thursday, the same time his wife, Kelly, 48, came home with groceries. Their daughter, who always kept them abreast of her whereabouts, wasn't home.
First, they called her cell phone, then her friends. A friend's mother suggested an AT&T Web site, which led them to her cell phone that was left inside her 1994 BMW parked near the tennis courts at the park.
"Because it was so out of character for Chelsea not to tell us or call us and say I'm going to be late ... we just had that feeling," Brent King said.
Kelly called 911 as her husband drove to the park. Brent looked first at the tennis courts, then saw a trail headed into the woods.
"I took off and ran down the trail as far as I could run, calling out for my daughter at the top of my voice in every direction," he said.
Chelsea was born in Poway, a well-to-do suburb of homes and office parks northeast of San Diego. The family followed Brent King's job in mortgage banking to the San Francisco Bay area and to the Chicago area before returning to San Diego. Their home was badly damaged in 2007 wildfires that ravaged Southern California.
Chelsea is taking four Advanced Placement courses and applied to 11 colleges, with an eye toward a career that would combine her interests in writing and environmental protection. She has been accepted to two schools, University of Washington and University of British Columbia.
"She is one of the most driven, personable, caring people that you could ever meet," Brent King said. "Her goal in life is to brighten everyone's day. That's what she does, and when she walks into the room, you know she's there."
She often stays up studying past midnight, working so hard that her parents urge her to ease off and spend more time with friends. Long-distance running was her escape.
"That was her outlet when she was stressed about a test or needed to just clear her head," Kelly King said.