Detective Anderson arrived at the scene, a dimly lit alley. A body lay on the ground, a single gunshot wound to the chest. A pool of blood surrounded the victim. An anonymous tip led the police to this location. The victim was identified as John Doe, age undisclosed. A crowd had gathered, eager for a glimpse of the crime scene. Anderson's partner, Detective Lee, arrived, briefcase in hand. "Let's find out who did this," said Lee. The investigation began.