Los Angeles, California (CNN) -- The parents of a California girl who was allegedly raped and killed by a registered sex offender are calling for tougher standards against repeat offenders.
"How many times do our daughters need to be raped before we put these monsters behind bars forever?" said Kelly King, mother of 17-year-old Chelsea King, in an interview Thursday with CNN's "Larry King Live."
"I just don't -- I don't get it. Change has to be made," she continued, "and I know that there are people out there that are trying to, you know, get this change in place."
She said she and her husband, Brent King, "are committed for the rest of our lives to be a part of that."
On Wednesday, John Albert Gardner III, 30, a registered sex offender, was charged in the rape and murder of Chelsea, who lived in the San Diego area. Gardner, who is being represented by a public defender, was also charged Wednesday with assault with intent to commit rape in an attack on a jogger in December 2009.
He pleaded not guilty to all charges. Gardner, of Lake Elsinore, California, will not be allowed to post bail.
If convicted, the charges against Gardner make him eligible for the death penalty, the San Diego County district attorney's office said Wednesday. The prosecutor's office said it has not determined whether it will seek capital punishment.
For the Kings, there's no question.
"I think the death penalty is a very appropriate punishment for this case," Kelly King.
Brent King said he had "100 percent agreement" with his wife.
Searchers found a body on Tuesday they believe to be that of Chelsea King. Police arrested Gardner on Sunday.
King had been missing since February 25. Investigators said she was last seen at her school in Poway, about 15 miles north of San Diego. Her car, with her cell phone inside, was found at Rancho Bernardo Community Park.
Searchers found remains in a shallow grave at that park; they were found along the shoreline of a tributary south of a lake, authorities said. The body was found in a heavily wooded area not visible from nearby homes. A shoe had been found earlier in the same area, the sheriff said.
King's parents, noting she was a great student and avid runner, said she had gone for a run at the park before she disappeared.
"It's a lovely area, very peaceful, very picturesque -- exactly what Chelsea ... loved to be in," Kelly King said.
She said the couple's son, 13-year-old Tyler, was extremely close to his sister. "He's struggling through it just like us," Brent King added.
Gardner's next court appearance, a status hearing, is scheduled for Tuesday. His preliminary hearing is scheduled for March 18.