The case had been falling apart. Everyone was upset because the evidence just didn't seem to be there. They had all given up for the night and headed home but Speed stayed behind in his lab. He was sure he could find something in the pile of possible evidence that he had on his table. He knew there was no such thing as a perfect crime. He was determined.
He sorted and categorized everything then began checking for any trace he could find. After what seemed like hours the mass spectrometer's printer buzzed to life and he had his answer.