The grandson and great-grandson of Chicago police officers, Chicago Police Detective James Sherlock was CPD through-and-through. His career had seen its share of twists and turns, from his time working undercover to thwart robberies on Chicago's L trains to his years as a homicide detective. He thought he had seen it all.

But on this day, he was at the records center to see the case file for the murder of John Hughes, who was seventeen years old when he was gunned down on Chicago's Southwest Side in 1976. The case's threads led everywhere: Police corruption. Hints of the Chicago Outfit. A crooked judge. Even the belief that the cover-up extended to "hizzoner" himself-legendary Chicago mayor Richard J. Daley.

A murder that had roiled the city and had been investigated for years had been reduced to a few reports and photographs. What should have been a massive file with notes and transcripts from dozens of interviews was nowhere to be found. Sherlock could have left the records center without the folder and cruised into retirement, and no one would have noticed.

Instead, he tucked the envelope under his arm and carried it outside.