The Zero Hour by Joseph Finder

FBI Special Agent Sarah Cahill is drawn into a murder investigation involving ex-husband homicide detective Peter Cronin. Meanwhile, across the ocean, charismatic terrorist operative Zero converses with Malcom Dyson, fugitive financier, who is hiring him to make a "hit." Sarah conducts an intense, secret manhunt for Zero, with no knowledge of his appearance. Finder again composes an intense thriller with believable scenarios, much to this reader's delight. A good read. Sandy Penton.