The killers, Nathan Leopold and Richard Loeb, were extremely wealthy and intelligent teenagers whose sole motive for killing Franks was the desire to commit the "perfect crime." Leopold, who graduated from the University of Chicago at age 18, spoke nine languages and had an IQ of 200, but purportedly had perverse sexual desires. Loeb, also unusually gifted, graduated from college at 17 and was fascinated with criminal psychology. The two made a highly unusual pact: Loeb, who was a homosexual, agreed to participate in Leopold's eccentric sexual practices in return for Leopold's cooperation with his criminal endeavors. Both were convinced that their intelligence and social privilege exempted them from the laws that bound other people.
In 1924, the pair began to put this maxim to the test by planning to commit a perfect murder. They each established false identities and began rehearsing the kidnapping and murder over and over. Loeb stabbed Bobbie Franks (who was actually his distant cousin) several times in the backseat of a rented car as Leopold drove through Chicago's heavy traffic. After Franks bled to death on the floor of the car, Leopold and Loeb threw his body in a previously scouted swamp and then disposed of the other evidence in various locations. In an attempt to throw police off their trail, they sent a ransom note demanding $10,000 to Franks' wealthy father.
But Leopold and Loeb had made a couple of key mistakes. First, the body, which was poorly hidden, was discovered the next day. This prompted an immediate search for the killers, which Loeb himself joined. The typewriter used to type the ransom note was recovered from a lake and, more important, a pair of glasses was found near Franks' body. When the glasses were traced to Loeb's optometrist, police learned that the optometrist had only written three such prescriptions. Two were immediately accounted for and the third belonged to Nathan Leopold, who calmly told detectives that he must have dropped them while bird hunting earlier in the week. This explanation might have proved sufficient, but reporters covering the case soon discovered other letters from Leopold that matched the ransom note. When confronted with this evidence, Leopold and Loeb both confessed.
Clarence Darrow agreed to defend Leopold, and the trial soon became a national sensation. Darrow, who didn't argue the boys' innocence, directed one of his most famous orations against the death penalty itself. The judge was swayed and imposed life sentences. Apparently unsatisfied with the attorney's work, Leopold's father later reneged on his contract to pay Darrow. In January 1936, a fellow inmate killed Loeb in a bloody razor fight in the prison's shower. Leopold was released on parole in 1958 with help from noted poet Carl Sandburg, who testified on his behalf. He lived out the rest of his life in Puerto Rico, where he died in 1971.