Before revision: Even if they cannot decrypt what suspects are saying to one another, a change of traffic may raise alarm, since a large increase may indicate increased preparation for action, while a sudden decrease may indicate the end of planning and the imminence of action.
After revision: in the volumeEven if they cannot decrypt what suspects are saying to one another, a change of traffic may raise alarm, since a large increase may indicate increased preparation for action, while a sudden decrease may indicate the end of planning and the imminence of action.