-LRB- CNN -RRB- -- Calling capital punishment in California an `` empty promise , '' the father of murdered teen Chelsea King said he supported a deal to take death off the table for his daughter 's killer in order to bring closure to the community . `` We stand here because of a despicable evil act committed against our beautiful daughter , Chelsea , committed against our family and committed against our community , '' Brent King said in a news conference Friday . `` While our unequivocal first choice is the death penalty , we acknowledge that in California that penalty has become an empty promise . '' San Diego County District Attorney Bonnie Dumanis said the family 's blessing contributed to a plea deal with registered sex offender John Gardner III in Chelsea 's death and two other cases . Gardner , 31 , pleaded guilty Friday to the murder of King , the murder of Amber Dubois , and assault with intent to commit rape of a third person . King , 17 , was last seen alive leaving Poway High School in suburban San Diego on February 25 . Her car , with her cell phone inside , was found at Rancho Bernardo Community Park , where she was known to run on the trails . Her disappearance sparked a massive search that ended a few days later with the discovery of her remains in the park . Dubois , 14 , disappeared in February 2009 while walking to school in Escondido . She was considered a missing person for more than a year , until her remains were found in March . Prosecutors revealed in court Friday that Gardner led authorities to Dubois ' body in exchange for assurances that it would not be used against him in court . In exchange for his guilty pleas , Gardner is to be sentenced to two consecutive terms of life without the possibility of parole . He also waived his right to appeals , ensuring that he will die in prison , Dumanis said at the news conference . Superior Court Judge David Danielsen accepted the plea and scheduled sentencing for June 1 . A gag order is in place until then . The surprise change of plea came during a hearing Friday , after prosecutors charged him with murder with a special circumstance of rape for Dubois 's death . Gardner was facing the death penalty on one charge of murder with a special circumstance of rape for King 's death . Dressed in dark blue jailhouse garb , his wrists chained , Gardner nervously responded `` yes '' several times to the judge 's questioning of whether he understood his rights and was entering his plea willingly . He cast his gaze downward as the judge read brief descriptions of how he raped and murdered Dubois and King . Gardner made no statement . According to court documents , on February 13 , 2009 , Gardner abducted Dubois and brought her to a remote area of Pala , where he raped and stabbed her , and buried her in a shallow grave . Gardner admitted to attacking King while she was running and dragging her to a remote area , the documents said . He raped and strangled her , and also buried her body in a shallow grave . Gardner also admitted to attacking another female on December 27 , 2009 , while she was running . In a news conference after Friday 's hearing , Dubois ' father , Moe , expressed gratitude over the case 's resolution . `` As you can imagine , this turn of events in the case came as a surprise to all of us when we were informed about the details yesterday , '' he said . `` As a parent I am thankful -LSB- for -RSB- the work put forth by the district attorney 's office and the defense team in coming forth with a resolution in the case and allowing us to have justice and closure for Amber 's case . '' Without the plea deal , Dumanis said her office did not have enough evidence to charge Gardner in the death of Dubois . Her remains were not found until Gardner led authorities to her body , three days after he was charged in King 's death , Dumanis said . `` The only promise made to him in exchange for this information was that we could not use it against him in court . This was a somber decision , '' the district attorney said in a press conference after Friday 's hearing , surrounded by tearful family members . `` To end the anguish of the unknown for the Dubois family and to bring Amber home , we agreed we would not use this information against Gardner in court . '' Further efforts to collect evidence linking Gardner to Dubois ' death were unsuccessful , Dumanis said , leaving her office otherwise unable to pursue charges against him -- until he offered to plead guilty . `` Accepting this plea has been an extremely difficult decision . We have the evidence to pursue a murder charge against the defendant for Chelsea 's murder , but not for Amber 's murder , '' she said . `` By accepting this guilty plea , we are obtaining a conviction for the murder of Amber that we otherwise would not have been able to obtain . '' The prosecutor also echoed the sentiments of King 's father on the death penalty in California , where 13 executions have been carried out since the U.S. Supreme Court reinstated capital punishment in 1976 . `` Most of us realize a death sentence at this time is a hollow promise in California . Even if death was imposed , Brent , Kelly and their family would have to endure a preliminary hearing , a trial , decades of appeals and the pain of reliving the murder over and over again , '' she said . `` In addition , as parents they realized what Amber 's parents were facing . Her case would have no legal closure . '' A resolution for the Dubois family also figured into the King family 's decision to support the plea , Brent King said . `` We find ourselves in a position to help give another grieving family a measure of closure . The Dubois family has been through unthinkable hell the past 14 months . We could n't imagine the confession to Amber 's murder never seeing the light of day , leaving an eternal question mark , '' he said . `` There 's nothing , nothing satisfying about this moment . It 's only one more unbearably painful day that we 'll have to carry in our memory as long as we live . ''