Bones by Jonathan Kellerman

A teen doing community service at the marsh gets the call.  The caller says there is a body in the marsh, and indeed there is.  Selena Bass, a local musician, whose main gig these days is teaching a genius child of a multi-millionaire.  Milo gets the call and goes to the scene, but calls in his friend, psychologist Alex Delaware.

By the next day, things have gotten worse.  Not only is Selena's body in the marsh, but so are the bodies of three other women.  All killed the same way, all buried facing the east, all missing their right hands.  Someone has found a game to play and is using the marsh as their private playground.

Milo and Alex start to work the case.  They have a new cop working with them, Jack Reed.  Milo teaches him the basics of investigation as well as the politics of getting along and getting things done in a big city police force.  There are plenty of suspects to work on.  There's the environmentalist who seems to regard the marsh as his private property and would prefer if no human beings ever came there to disturb the local birds and environment.  There's a caretaker at the millionaire's house who seems a bit off, a bit worried by a police inquiry.  It turns out that Selena may have been mixed up in some offbeat pursuits of her own.  Can Milo and Alex solve this case before anyone else gets hurt?

This is the 23rd Alex Delaware mystery written by Jonathan Kellerman.  Readers will quickly see why he is considered in the top echelon of mystery writers.  Kellerman's own background as a clinical psychologist makes the medical theories ring true, and he knows how to racket up the suspense as few other authors can.  This book is recommended for mystery fans.