Assumed identity - David Morrell

It is the ultimate nightmare of a deep-cover specialist to come face-to-face with someone from a previous mission. In the middle of a dangerous operation in Mexico, Brendan Buchanan is hailed by a man who knew him from another time and place. This meeting spells catastrophe for one who has spent all of his professional life under assumed identities in many of the world's most perilous places. And the consequence is that Buchanan's career could be terminated. Just like Buchanan himself.