Franko was last seen walking to his school on the morning of May 8, 1983 in Lemmon Valley, Nevada. He was a fifth grade student at the time, and was a member of the 4-H Club. He never arrived at school and has never been heard from again.

A defrocked priest named Stephen Kiesle became a suspect in Franko's case in mid-2002. He has since been arrested and charged with molesting three girls at the Santa Paula Catholic Church in Fremont, where he worked from 1968 to 1971. Police searched his yard three times, using cadaver-sniffing dogs, radar, and a backhoe. They were looking not only for evidence in Franko'sdisappearance but also evidence in the disappearances of Jaycee Dugard, Amber Swartz-Garcia and Jennifer Martin. The only item that was located was a bag full of dirt and decomposed clothing. The searches concluded in July 2002.

Franko is believed to have been abducted by a non-family member, but few details are available in his case.