Absolute Power by David Baldacci

A burglar in the bedroom of a mansion has his work interrupted by the arrival of the mistress of the house with the president of the U.S. The couple have a fight and she is killed. The burglar flees, taking along a blood-stained letter opener as evidence, but is spotted by presidential bodyguards. The White House chief-of-staff, an ambitious woman, has him tracked and killed, but not before the burglar has told his story to a lawyer. The lawyer realizes he is next, but how to save oneself from the government? A first novel.