John Albert Gardner III, 31, also faces an additional 33 years to life in prison for assaulting a woman Dec. 27.

Gardner, whose plea spares him from a possible death sentence, is scheduled to be sentenced June 1.

His plea also bars him from filing an appeal of his conviction and sentence.

Gardner admitted attacking, raping and killing 17-year-old Chelsea King, who disappeared after going for a run Feb. 25 at Rancho Bernardo Community Park. The avid runner and straight-A student's body was discovered five days later in a shallow grave near a tributary of nearby Lake Hodges -- not far from Gardner's mother's home.

Searchers combing woods, marshes and swamps in northeastern San Diego for a sixth straight day early Tuesday afternoon found a body believed to be that of the missing teen in a shallow grave at the edge of Lake Hodges.

Paul Pfingst says that Gardner's parents can't be charged. "Mr. Gardner has the responsibility of registering with law enforcement. Not his mother, not his father. They are not responsible if he railed to fulfill that obligation, even if they knew it," Pfingst told 10 News.

Pfingst says more focus is needed on violent sex offenders. There are may types of sex offenders and not all are equally dangerous. "We have to trim the list of that 60,000 down to a number of truly dangerous people and then intensively supervise them. Somebody who downloads a pornographic image from the Internet is very different from somebody who beats up and savages somebody during the course of a rape. Megan's Law treats them the same," said Pfingst.

“Although positive identification has not been made, there is (a) strong likelihood that we have found Chelsea,” Sheriff Bill Gore several hours later, shortly after breaking the news to the girl’s parents. A member of a law enforcement dive team found the body shortly after 1 p.m. in a remote, secluded spot on the south side of the lake, about 10 feet from the water’s edge, Gore said.

His not guilty plea was entered on his behalf by one of his attorneys, Michael Popkins. The defendant was ordered back to court Tuesday, and a preliminary hearing was tentatively scheduled for March 18.

Superior Court Judge Joseph Brannigan ordered Gardner held without bail. Friends, family, reporters and other officials packed the courtroom during the arraignment. Members of Chelsea's family -- including her parents, Brent and Kelly -- attended the hearing but did not speak with reporters afterward.