Franks was the son of Chicago millionaire Jacob Franks and a neighbor and second cousin of Richard Loeb. Leopold and Loeb had no financial motive for their act; they kidnapped and murdered Franks because they wanted to commit the perfect crime. Franks, whose family lived across the street from the Loeb family mansion, was chosen as if at random on the day of the murder. The press soon dubbed the murder a "thrill killing".
His corpse was left in a drainage pipe at Wolf Lake, approximately 15 miles south of the Chicago Loop. The police soon found enough evidence to arrest Leopold and Loeb, both men blaming the other for the actual murder. Although they were expected to be executed they were defended by famed attorney Clarence Darrow and received life sentences for the murder and 99 years for the kidnapping, following a trial which was declared by the press as the "trial of the century". Loeb was murdered by a fellow prison inmate in 1936. Leopold was paroled in 1958 and relocated to Puerto Rico. He died of a heart attack in 1971.
If it had not been for a dentist's appointment, the victim of this murder might have been 11-year-old Armand Deutsch, grandson of Julius Rosenwald. After leaving school that day, Armand was picked up by his family's chauffeur. Bobby Franks was randomly chosen for this murder instead. Deutsch lived to be 92.