Preston, Douglas J. Pendergast novel.

After an overhaul of leadership at the FBI's New York field office, A. X. L. Pendergast is abruptly forced to accept an unthinkable condition of continued employment: the famously rogue agent must now work with a partner. Pendergast and his new teammate, junior agent Coldmoon, are assigned to Miami Beach, where a rash of killings by a bloodthirsty psychopath are distinguished by a confounding M.O.: cutting out the hearts of his victims and leaving them - along with cryptic handwritten letters - at local gravestones, unconnected save in one bizarre way: all belonged to women who committed suicide