SAN DIEGO -- An August 4 preliminary hearing date was set Tuesday for a registered sex offender charged with the rape-murder of a Poway High School senior who vanished while running behind Rancho Bernardo Community Park.

John Albert Gardner III, 30, could face the death penalty if convicted of murder and a special circumstance allegation of murder during the commission of a rape or attempted rape.

District Attorney Bonnie Dumanis will decide after the August hearing whether Gardner will face the death penalty or life in prison without the possibility of parole if he's convicted of killing Chelsea King.

Gardner was arrested Feb. 28 in connection with the 17-year-old cross-country runner's disappearance three days earlier. Her body was discovered March 2 in a shallow grave in a tributary of nearby Lake Hodges.

According to Escondido police, Gardner is also the focus of an investigation into the disappearance and murder of 14-year-old Amber Dubois, who went missing 13 months ago. Her skeletal remains were discovered in a remote area of Pala on Saturday.

Her father, Moe, attended Tuesday's hearing for Gardner and said he and Amber's mother, Carrie McGonigle, are the only people who represent the true feelings of their family.

The father was reacting to statements by others, including private investigator Bill Garcia, who said he was told that a tip that led investigators to Amber's body did not come from Gardner, who has not been charged in connection with the girl's death.

"The only spokesperson for Amber and Amber's family will be me or Carrie," he said.

Moe Dubois asked the media to use its resources toward finding missing children like Michael Guidry, who has been missing in San Diego since Thanksgiving.

"There are many other children in the area who do need your help and need your support," Dubois said. "You have the power to bring these children home. Please use that power and attention on those children at this time."

The father refused to answer questions on whether he thought Gardner was linked to his daughter's disappearance and murder.

At Tuesday's hearing, Judge David Danielsen signed a protective order barring attorneys and police involved with Gardner's case from releasing any information to the news media.

Gardner is also charged with an attack on a Colorado woman who was running alone in Rancho Bernardo Community Park last Dec. 27.

According to public records, Gardner was convicted of assaulting and molesting a 13-year-old neighbor in 2000. The victim said he repeatedly punched her in the face and fondled her at his mother's townhouse, which is about a mile from Rancho Bernardo Community Park. The girl said she went to the residence after Gardner invited her in to watch a movie.

Gardner was sentenced to six years in prison and served five before he was released in September 2005. He was on probation until 2008. He registered as a sex offender using his grandmother's Lake Elsinore address but reportedly had been staying with his mother lately.

A probation report prepared for that sentencing was released Tuesday after Danielsen granted a request by the San Diego Union-Tribune and 10News that it be unsealed and made available for public viewing.