SAN DIEGO — With two teary-eyed mothers looking on, convicted sex offender John Albert Gardner pleaded guilty Friday to raping and murdering their teenage daughters.

Gardner, 31, admitted kidnapping, raping and stabbing 14-year-old Amber Dubois, and dragging 17-year-old Chelsea King to a remote area where he raped, strangled and buried her.

As part of the plea deal, he also admitted trying to rape a female jogger last year in San Diego who managed to escape.

— From wire reports

Gardner, wearing a dark blue jail jumpsuit with his shackled arms hanging at his sides, said nothing but “yes” repeatedly as the judge asked him for his pleas.

He faces life in prison without parole and has waived his right to appeal.

Parents Brent and Kelly King, and Maurice Dubois and Carrie McGonigle were in the courtroom to hear the admissions. Kelly King and McGonigle were teary-eyed throughout the proceeding.

The two families agreed to accept Gardner’s plea deal with prosecutors, who said they would not seek the death penalty if he pleaded guilty to both murders.

“There’s nothing satisfying about this moment. It is only one more unbearably painful day that we will have to carry in our memory as long as we live,” Brent King said after the hearing.

“Accepting this plea has been an extremely difficult decision,” added District Attorney Bonnie Dumanis. “We have the evidence to pursue a murder charge against the defendant for Chelsea’s murder, but not for Amber’s murder.”

Gardner served five years in prison after pleading guilty in 2000 to molesting a 13-year-old neighbor girl. Records show he later violated parole by moving too close to a school but was allowed to remain free.

His treatment has led to calls to strengthen California’s already stringent laws on sex predators.

Chelsea King disappeared Feb. 25 during an afternoon run in a San Diego park. Her body was discovered five days later in a shallow lakeside grave after a massive search for the straight-A student and member of the Poway High School cross-country team.

Gardner was arrested three days after she disappeared and initially pleaded not guilty to her killing. Prosecutors said he was linked to the crime by DNA found on her clothing.

Two days after authorities charged Gardner, he agreed to lead them to the bones of Amber if they did not go public with the information or use it against him in court.

Officials, however, retained the ability to use any evidence obtained from the crime scene to build their case.

“This was a somber decision,” Dumanis said. “To end the anguish of the unknown for the Dubois family and to bring Amber home, we agreed.”

Escondido police and crime lab technicians worked round-the-clock to find evidence linking Gardner to her murder, but Dumanis said they did not succeed.