( CNN ) -- Carrie McGonigle does n't want to believe that her missing daughter could be connected to a registered sex offender accused of killing a California teen . `` That would mean that she 's dead , and I do n't want to think that , '' said McGonigle , whose 14-year-old daughter , Amber DuBois , was last seen walking alone to school on February 13 , 2009 . But authorities say they are looking into whether John Albert Gardner III , who pleaded not guilty Wednesday to raping and murdering Chelsea King , was involved in Amber 's disappearance . `` We have been working closely with San Diego Sheriff 's Office , and our investigators are working with theirs in case there is a connection , '' Lt. Robert Benton with the Escondido , California , Police Department said . `` We are involved in the daily briefings on the King investigation . '' Amber 's father , Moe DuBois , attended Gardner 's arraignment Wednesday . `` Just the similarities in our case , you know , if there is any connection to Mr. Gardner and our case , I want to be there for his prosecution and soon to be execution I would hope , '' DuBois told HLN 's Nancy Grace . Amber 's family lives in the San Diego , California , suburb of Escondido , less than 10 miles from Poway High School , where King was last seen alive . The shy , bookish teen was walking to Escondido High when she disappeared . She had a check in her backpack to buy a lamb for a Future Farmers of America project , according to her mother . But she never made it , and since then , investigators have been stymied by a lack of viable leads . McGonigle says Gardner came up on her radar shortly after Amber disappeared , when she began looking up registered sex offenders in the area . `` One of the first things we did when we could n't find her was look at the sex offenders in the area because we know that they have a history of repeated offenses , '' McGonigle said . `` I did n't personally visit his home but one of our volunteers did , and we did n't find anything that raised suspicions . '' Gardner is on California 's sex offender registry for a conviction of lewd or lascivious acts with a child under 14 , according to online records . He was also charged Wednesday with assault with intent to commit rape in connection with an attack on a jogger in December 2009 . A call to Gardner 's public defender , Michael Popkins , was not immediately returned . In addition to keeping the search going for her daughter , McGonigle has also become involved in educating parents and children on how to prevent abductions . She also spends time reaching out to parents of other missing children . As soon as she learned of Chelsea 's disappearance , McGonigle says she contacted Chelsea 's parents and assisted in search efforts . Chelsea 's car , with her cell phone inside , was found at the Rancho Bernardo Community Park , where she was known to go for runs . `` Ever since Amber went missing I 've reached out to all the parents I possibly can because once it happens to you , it 's going to be with you the rest of your life , '' she said . `` It becomes your life . Supporting families , that 's what it 's all about . Even when we find Amber , I 'll continue because I would n't want any other family to go through this . '' Searchers found a body Tuesday that they believe to be King 's , San Diego County Sheriff William Gore said at a news conference Tuesday . He said he expected a positive identification of the body to come this week . To some in Amber 's family , Chelsea 's disappearance has other stinging implications . `` It 's heartbreaking in another way because now we know of everything that was available to search for Amber but was n't used , '' Sheila Welch said . `` There were n't helicopters used with heat sensitivities , there were n't any dogs brought out for Amber , and now to know that 's available , it 's heartbreaking to think it was n't used . '' But Benton said investigators used all the resources available to them . `` We asked for and received the resources we needed at the time , '' he said . `` As far as law enforcement is concerned , we had outstanding cooperation from local agencies , the FBI , the National Center for Missing and Exploited Children , and we had a significant amount of resources at our disposal . '' Amber 's mother has her doubts as to whether Gardner could actually be involved . `` I think the guy is too sloppy and that we would 've found some evidence if he had taken Amber , '' she said . `` But he never should have been out in public . If he were incarcerated , like he should have been , maybe Chelsea would be alive right now . ''
Authorities probe whether John Albert Gardner III was involved in Amber DuBois ' disappearance . Gardner , a registered sex offender , has pleaded not guilty to killing Chelsea King , 17 . Amber was last seen walking to school on February 13 , 2009 , a few miles from Chelsea 's school . Chelsea also last seen at school ; her car was found in park last week .