The Cutie by Donald Westlake
The first novel by Westlake published under his own name, this is a good if somewhat confused effort. The protagonist, Clay, is he right-hand man of an "organization" boss. However, he is working in this plot as something of a detective to find out who killed a number of people. Clay is no Parker (who would hit the scene a couple years later). And Westlake's immaturity as a writer is evident in a number of places. But it's a decent read and is interesting to compare to The Hunter.