ALPHA, by Stephen L. Brayton
On a rainy October morning, Mallory Petersen, private detective and martial artist, discovers the corpse of her boyfriend, Bobby Furillo, in front of her office in Des Moines.
Bucking police authority and continually attacked by unknown adversaries, Mallory uncovers Bobby's devastating secrets. Each new revelation puts Mallory in deeper peril from powerful and dangerous people. And just what are those enigmatic RSVP cards that keep showing up in Mallory's mail?