What was the motive for killing Bobby? Why would Loeb risk killing his own neighbor? Although some of the accounts differ, it seems Loeb had a plan to mastermind a series of terrible crimes. Bobby was the first murder victim.
The day Leopold and Loeb killed Bobby Franks was not the first day they had engaged in crime, however. While undergraduate students at the University of Michigan, they had stolen a typewriter from a fellow student's dorm room. Although they got away with burglary at the time, that stolen typewriter would come back to haunt them. (Scroll down 80% of the page on this link to read about the typewriter burglary.)
Part of Loeb's plan was to ask for ransom money. The young men prepared a ransom note which Leopold typed on his stolen, portable typewriter. After he typed the message, Leopold and his best friend separated the typewriter keys from the case and dumped each into different lakes. They sent the note to Jacob Franks, Bobby's wealthy father.
Since money was no problem for the Franks, the demand for $10,000 in "old bills" was manageable. The note said Bobby was still alive. Mr. Franks would certainly cooperate - and would certainly keep the police out of it - as Leopold, disguised as "George Johnson," required when he made the "kidnapper's phone call" to the Franks.
But Bobby was not alive, and Leopold and Loeb were about to learn that their "perfect crime" was not so perfect. A series of "chance" events led to their capture within a week.