Authorities said Monday they have strong "physical evidence" linking a registered sex offender to the disappearance of suburban San Diego teenager Chelsea King.

Investigators arrested 30-year-old John Albert Gardner on suspicion of rape and murder in connection with her disappearance.

The arrest came Sunday after 120 law enforcement officers and 1,400 volunteers scoured Rancho Bernardo Community Park in San Diego for the 17-year-old honor student.

"Evidence found in the last few days at the scene has led us to Gardner," Jan Caldwell, a spokeswoman for the San Diego County Sheriff, told Fox News in an interview Monday.

Caldwell, who would not elaborate on the specific nature of the evidence, said investigators continue to comb the area around Lake Hodges in the park where Chelsea's car was found.

SanDiego6.com reported Monday that underwear found near the lake contained DNA that lead investigators to Gardner.

Gardner was taken into custody outside a business in Escondido shortly after 4 p.m. Sunday.

"I think our best clue is who the sheriff's department has arrested," Chelsea's father, Brent King, told Fox News.

"She is every parent's dream," added her mother, Kelly, who described the straight-A student and long-distance runner as "bright, outgoing and compassionate."

On Sunday, San Diego Police Chief Bill Gore told reporters that the investigation is "ongoing" and that "specific criminal charges are still being determined."

Investigators also suspect Gardner could be tied to a Dec. 27 assault on a female jogger from Colorado Springs, Colo. in the park, a popular regional recreation area full of running trails, Gore said.

Gardner is from Lake Elsinore some 75 miles north of San Diego, according to the Megan's Law Web site. He had to register as a sex offender because of a conviction for lewd or lascivious acts with a child under 14, the site said.

It was not immediately clear whether Gardner has hired an attorney.

Caldwell said the search for King and for further evidence would continue throughout the day and expand beyond the park.

"The search and rescue efforts here are almost unprecedented," she said. "They have literally moved heaven and earth to find this little girl."

Over 2,500 volunteers also handed out flyers during the weekend effort.

"It's a reflection of who she is and what kind of person she is," Brent King said of the numbers showing up to help. "She's that kind of kid that everybody loves, and it shows."

Chelsea King's BMW was found in the park after she failed to return to her home in suburban Poway, Calif. on Thursday.

Investigators also looked for clues on the teen's cell phone, which was found in her car, and on her home computer.

The search for Chelsea King, an honor student and senior at Poway High School, also took to the Internet, where a Facebook page generated more than 24,000 fans. A Web site was created at findchelsea.com.

Family spokesomwan Stephanie Dorian told FoxNews.com Sunday that Chelsea, a peer counselor and french horn player with the San Diego Youth Symphony, "usually didn't run alone."

"She's incredibly intelligent, well-liked and beautiful," Dorian said. "This is the most horrific nightmare you could ever imagine."

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Click here to visit FindChelsea.com

The Associated Press contributed to this report.