When undercover vice officers pulled over a car at 11th and O streets in northwest Washington on a warm spring evening in 1998, they thought they were about to make just another routine drug bust. But they had stumbled upon a gold mine.

The driver, a Northern Virginia man in his late 20s, was nabbed with a known drug dealer in his car. He flipped and soon became the chief informant in 190 drug buys from other street dealers. The U.S. attorney’s office subsequently made nearly 100 cases in D.C. Superior Court due to his cooperation.