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 . `` 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 . Police have said they are looking for Gardner, who is believed to be armed and dangerous.
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 . Police have said they are looking for Gardner, who is believed to be armed and dangerous.