The Coffin Dancer (Lincoln Rhyme #2) by Jeffery Deaver

NYPD criminalist Lincoln Rhyme joins his beautiful protege, Amelia Sachs, in the hunt for the Coffin Dancer--an ingenious killer who changes appearance even faster than he adds to his trail of victims. They have only one clue: the madman has a tattoo of the Grim Reaper waltzing with a woman.

Rhyme must rely on his wits and intuition to track the elusive murderer through New York City--knowing they have only forty-eight hours before the Coffin Dancer strikes again.