Chelsea King, 17, was reported missing after going for a run in San Diego, Calif., last Thursday. Her cell phone and iPod were found in her car at Rancho Bernardo Community Park.
Hundreds of volunteers continued to search the park Monday for the teen, whose family moved from Naperville to San Diego three years ago.
Investigators said evidence found in the park led to the arrest of John Albert Gardner III of Lake Elsinore, which is in Riverside County, 75 miles north of San Diego. The 30-year-old is a registered sex offender who may also be tied to an assault on another jogger on December 27. He was required to register as a sex offender because of a conviction for lewd or lascivious acts with a child under 14, the Megan's Law Web site said.
Gardner was taken into custody Sunday.
"This investigation is ongoing and specific criminal charges are still being determined," San Diego County Sheriff William Gore said at a news conference Sunday.
Those in Naperville who know King say she has a contagious smile and zest for life that made her stand out in California and Naperville. Now, 30-year-old John Gardner, a registered sex offender, is being held in her disappearance.
"We love her so much, and we just want her back," said dad Brent King. "You can't say enough. It is so heart warming to see the effort that's being given, and it's what sustains me every single moment."
In Naperville, King's education started at May Watts Elementary. She went on to Hill Middle School and Waubonsie Valley High School in Aurora. Her enthusiasm touched her teachers.
"Chelsea was one of those children who just tugged on your heart strings. She worked so hard," said former teacher Sandy Sobin. "She was such a good student. She always did her best. She was a really sweet little girl."
And King kept in touch with a tight-knit circle of friends in Naperville.
"I just felt like she was my second daughter. She was here all the time," said family friend Lisa Nowell.
"Honestly, everyone that met her fell in love with her," said family friend Alex Nowell.
"I have never met anybody as driven as her," said Jennifer Nowell, who became friends with King when they were 5.
"The kids are just beside themselves. They love Chelsea like a sister, each and every one who's been friends with her," said family friend Kathy Ferguson.
And that's why on Sunday night, more than 100 people gathered at St. Thomas the Apostle Church. They prayed. It was a chance for them to be together.
"People want to be in solidarity with the family and with each other during this hard time. And we stand ready to support them and the family any way we can," said Father Joel Fortier, St. Thomas the Apostle.
In fact, some friends have flown to San Diego, supporting the family and helping with the search effort. Gary Hill's wife, Katie, is one of them. She's been with Chelsea King's parents.
"Very stressed out and just hoping and praying that everything works out positively in the end," Gary Hill. "I know they are on pins and needles to get positive news and see Chelsea as soon as possible."
"How can anybody hurt her? Everybody loved her," Ferguson said.
Ferguson's daughter and King grew up together in Naperville. She said King still has a tight circle of friends there.
"Everyone would just like to jump on a plane and take care of the family and be on the lookout for Chelsea," Ferguson said.
"As soon as we heard of the situation, all thoughts went to helping them and making sure we get the safe return of Chelsea," Gary Hill said."The more we can publicize the disappearance and get Chelsea's picture out there, and the suspect's picture out there, that helps the investigation," said Sheriff Gore. "We're not stopping. We're going to continue our search and cover every tip and lead that comes in. So we're not gonna rest until this is succesfully solved, bringing Chelsea back home."
"Nothing will change for us until our beautiful daughter, Chelsea King, comes home," Brent and Kelly King said in a statement released through a family spokeswoman. "We will continue searching for her, and we ask that all of you do the same until she's back with us."
Gore said the search for King and for further evidence would continue through Monday night and expand beyond the park.
"There are several searches going on around the county," Gore said. "We are going to refocus some of our search efforts."
The search for the straight-A senior at Poway High School also took to the Internet, where a Facebook page generated more than 45,000 fans. A Web site was created at findchelsea.com.
The Associated Press contributed to this report.