scalphunter

plural scalphunters

1. A warrior who collects the scalps of vanquished enemies.
2. espionageAn agent who vets potential defectors.

   But agency policy is that the case officer is, in the jargon, a "scalp hunter" who must turn a contact into an agent […]

   2002, Angelo Codevilla, Informing Statecraft, page 82

   1 more example

   There is one class of spook we have not encountered as yet. This is the scalp-hunter, or defector-hunter. Quite often a scalp-hunter will be more valuable than almost any other intelligence operator.

   1982, Richard Deacon, With My Little Eye: The Memoirs of a Spy-Hunter, page 103