The devil's teardrop

On the last day of 1999, Washington, D.C., is paralyzed by terror. A morning machine-gun massacre at the Dupont Circle Metro station has left dozens dead. A message sent to the mayor's office claims the killings were carried out by the Digger, a mechanical-seeming hitman set to strike the capital every four hours until midnight. The writer demands $20 million, to be handed over to the Digger's partner, who is also the scheme's architect.

The plan begins to unravel when that partner dies in a bizarre accident on the way to the ransom drop. The only real clue left is the ransom note. Special Agent Margaret Lukas turns to Parker Kincaid, a retired FBI agent widely regarded as the country's leading forensic document examiner. Working against the clock, the two must track down the Digger before midnight, while he is hunting them too.