"Executive Privilege" By Phillip Margolin, Harper Collins, $25.95

Could the president of the United States be a serial killer? In this day and age, presidents have been accused of worse things. And if that unthinkable scenario should be the case, is it possible for an investigator to stay alive long enough to prove it?

In "Executive Privilege" Phillip Margolin sets up a situation in which the sitting President's guilt is not only possible but very likely, and he writes so brilliantly and plots his novel so cannily that the reader can never be in doubt of the possibility.

Not that any American president would have to dirty his hands by doing the deed himself. Margolin's fictitious chief, Christopher Farrington, who is running for re-election, has a ruthless and competent hatchet man named Chuck Hawkins, an ex-marine whose loyalty to his boss is blind and unwavering.

Two separate and unrelated events occur that cast suspicion on Farrington's actions. Dana Cutler, a D.C. private detective, gets an assignment from a lawyer with high political connections that involves following a young female student, who seems to be stealing campaign materials from the challenging candidate's office. Dana follows the student to a farmhouse, only to see and photograph the girl with President Farrington. It's pretty obvious that they have been having a love tryst.

Two Secret Servicemen see Dana taking the photographs, and to escape with her own life, Dana shoots one of them. She is attacked in her home but escapes, and goes on the run.. Next day, the student turns up dead, apparently murdered by a serial killer known to be on the loose in the area.

In Portland Oregon -- Farrington's home state -- a young lawyer named Brad Miller is assigned to defend (pro bono) a confessed serial killer on death row. The killer has admitted to the murders of several young women but not the last one. When he gives Miller confidential evidence that he could not have killed the last girl, the lawyer investigates on his own.

Both Cutler and Miller -- separately -- begin to suspect the President's complicity, but they have no proof, and the more evidence they acquire, the closer they are to being killed themselves. Almost everyone connected with state and federal governments seems to be dishonest, and the body count is increasing. It takes an honest FBI agent to put Cutler's and Miller's stories together, but then the agent is in danger as well.

Margolin has mastered all the elements of a successful suspense mystery. The action moves quickly. His prose is compelling: nothing is what it seems, and there are surprises even after the reader has been fooled into thinking the mystery is solved.

Margolin knows how to manipulate his characters and readers alike, but we don't mind, because he does it so well and takes us in so thoroughly.