Blood Innocents by Thomas H. Cook

In Thomas H. Cook's Edgar Award-nominated first novel, a weary detective tracks a blood-crazed psychopath Blood seeps into the gutters at the children's zoo in Central Park. Two deer have been slaughtered, one stabbed fifty-seven times and the other slashed across the neck. Normally it would be a case for the Parks Department, but these are no ordinary deer. The pride of the small menagerie, they were given to the zoo by a prominent socialite who cannot afford bloody headlines. The NYPD hands the case to Detective Reardon, star of the homicide squad. A recent widower at fifty-six, Reardon has seen too many human victims to care much about the two butchered animals. He resents being taken off other pressing cases for the sake of politics, but soon another killing snaps him to attention. Two women are found dead in their apartment, one stabbed fifty-seven times and the other with her throat cut. Surely this vicious parallel isn't a coincidence..