Despite their best-laid plans, and despite their "solid" alibis, Leopold and Loeb confessed on May 31, 1924 - just ten days after the killing. Here is the article from
The Chicago Daily News that reports how they cracked.
It's interesting to note they broke about the same time, but they took different paths to get to the truth.
As the newspaper account makes clear, the evidence against Leopold and Loeb was just too strong. The typewriter they had stolen from their U of M classmate now took center stage. The evidence from an earlier, unsolved burglary gave prosecutors the key to unlock an unsolved murder. The typewriter proved to be the final clincher.
As Loeb watched the evidence mount against him, he saw the perfect opportunity. Leopold had confessed. Why not blame him for the whole crime? After all, the glasses were Nathan's. So was the typewriter. True to character, he blamed his best friend. But by previously telling authorities he had unwittingly dropped the typewriter into a lake, Loeb had given authorities what they needed. They knew where to search for the typewriter. Loeb had sealed his own fate too. When asked why they did it, folks who knew the boys speculated it was for the "experience."
Since Leopold had already confessed, the charade was over. The prosecutors were ecstatic they had solved this horrible murder case. They would ask for the death penalty. But not just yet. First they had to pose for pictures with the two criminals.
Even confessions have to be tested in court. Even indisputable evidence needs to be weighed at trial. Before the prosecutors could get the death penalty, they had to try the case against Leopold and Loeb. How did the defendants' lawyer respond to the charges? Not guilty, of course.