HOW COPS GO BAD

It was around 8 o'clock in the evening of Feb. 24, 1991, and Arthur Colbert was lost. Most of the rest of the world was focused on the Persian Gulf, where the ground war had begun only hours earlier, but Colbert had a woman on his mind. His date for the night lived in a Philadelphia neighborhood known for its crime and poverty, and Colbert couldn't find her house. Then he got lucky--or so he thought. A police wagon was idling down the block, and Colbert got out of his dark blue 1985 Toyota Camry to ask directions. Inside the police...