Disappearance

WITSEC, the witness protection program run by the U.S. Marshals Service, has been in existence for forty-six years. In all that time, WITSEC has never lost a witness who remained in the program, a total of 8500 witnesses in that time. What if, suddenly, two witnesses were murdered, execution-style, and an attempt was made to assassinate a third witness but barely failed...all in a span of two weeks?
There is a leak in the U.S. Marshals witness protection unit, or a massive breach in their computer system. Paul O'Malley, the director of WITSEC, must stop the killing before many witnesses lose faith in the program, and seek new sanctuaries on their own. O'Malley, with the keen help of a long-time ally and friend, retired FBI agent Harry Esten, team up to identify the leak and stop further killings.
Esten's years of investigations significantly contribute to unfolding the assassin and the former marshal who is providing him with the names of victims who have continued to commit crimes while in WITSEC.
The trail of both villains becomes clearer to the bumbling O'Malley, while Esten's thorough research gets O'Malley back in the chase more often than not.
There is non-stop action throughout, leading to a climactic confrontation between the two villains, and an ending that will surprise everyone.