By November 1923, Leopold and Loeb had explored and discarded a number of criminal scenarios, which they felt would test their intellectual skills. They decided that a kidnapping of a wealthy young boy for ransom would provide the greatest challenge; especially the skill and planning that would be required in retrieving the ransom without being caught. Loeb maintained that the killing of the kidnap victim was essential to preserve their anonymity, Leopold was less sanguine about this element of the plan but, as usual, went along with Loeb’s demands: his infatuation with his friend was undiminished.
After an extensive amount of research, they decided on a complicated plan that involved sending the victim’s father to a pre-arranged place, where they would call him and demand that he board a specific train, with very little notice, to reduce the possibility of police being able to follow. Once on the train, a hidden note would inform him exactly where to throw the ransom money from the train, where the pair would be waiting to retrieve it, before making good their escape.
Despite the depth of planning, they decided that the victim would be a purely random choice: there was no shortage of wealthy victims in their own neighbourhood and they merely required that the victim be known to one of them, in order to ensure that he could be lured into their car with ease. As they planned to kill the victim immediately, there would be no problem with later identification. Leopold was a keen ornithologist, and was familiar with an area called Wolf Lake, where he had discovered a secluded culvert suitable for dumping the body: in addition to it being a relatively isolated area, it would avoid the necessity of digging a grave.
On 21 May 1924 they put their plan into action, collecting a rental car, obscuring its number plates and then driving to their old alma mater, the Harvard School, in search of a convenient victim who met their prerequisites. They considered and rejected a number of candidates, until 14-year old Bobby Franks emerged. A neighbour of the Loebs, who often played tennis on the Loeb’s courts, he met the wealth and familiarity criteria, and his fate was sealed.
Lured into the car, he was hit over the head with a chisel by Loeb and then gagged, before being hidden under some blankets on the back seat of the car. It is unclear whether he died immediately from the blow, or later from suffocation. They stopped briefly on the trip to Wolf Lake, to strip the boy and discard his clothing, as well as calling the Franks’ family home to tell them to await a ransom demand. When they arrived at Wolf Lake they took the now-dead boy out of the car, and poured acid on his face & genitals, apparently to delay his identification (his circumcision would have identified him as Jewish). A later post-mortem indicated that Bobby Franks’ rectum had been dilated, but there were no signs of overt sexual activity, the development of forensic science being then in its infancy.
After depositing Franks’ body in the culvert, they returned to Kenwood, meticulously cleaned the hire car, disposed of their own clothes and the chisel, and prepared the ransom note, which demanded $10,000 in used notes, to be prepared for delivery by Bobby Franks’ father the next day, to a destination that would be revealed in a phone call. The note was signed George Johnson.
The next morning they called Jacob Franks with an instruction that he should take a taxi, which the pair had pre-arranged, to a drugstore where they would call with further instructions, namely to board the designated train for the final drop. Unbeknownst to Leopold & Loeb, Franks had contacted the police, and Bobby Franks’ body was found and identified far sooner than they expected: as Jacob Franks was about to leave to deliver the ransom, he received a call confirming that a body of a young boy, found near Wolf Lake, was that of his son.
When Leopold and Loeb tried calling Franks at the drugstore, as arranged, and received no reply, they realised that their meticulously planned ‘perfect murder’ had gone awry, although at that stage they had no idea exactly what had caused its failure.
Given the wealth and social standing of the victim’s family, not to mention their political connections, the case was front-page news from the outset. Several rewards for information were offered, and a large contingent of local authorities was assigned to investigate the case.