If principles of intelligence tradecraft have not been strictly observed, it is also possible that compromised agents can reveal information that exposes other members of the network.
If an agent is able to resist interrogation for a defined period of time, the odds improve that other members of the network can be alerted to the compromise.
Most importantly, case officers train agents in methods of avoiding detection by host nation counter-intelligence organizations.
Identifying potential agents, and investigating the details of their personal and professional lives, involves the granular verification of their bona fides.
Such activities can include uncovering personal details that leave potential agents vulnerable to coercion, blackmail, or other inducements, such as sexual approaches.
Other elements of tradecraft include elicitation, surveillance and countersurveillance, photography and the emplacement of audio devices, sensors, or other transmitters.
Case officers generally train agents one at a time, in isolation, including only those elements of tradecraft needed to penetrate the target at hand.