Payback by Mike Lupica

 After Robert Parker died, several different writers took over his various series--with mixed success. Mike Lupica took over the Sunny Randall series and he seems to have found the right tone. In Payback, Sunny is hired by her cop friend Lee to find his college-age niece, Emily. She is also trying to help her best friend Spike when he loses his bar to a shifty hedge-fund manager named Alex, who soon turns up dead. Sunny eventually realizes that her two cases may be connected and that there may be some serious bad guys involved. Good story that moves right along.