This paper investigates the role of evidence production in the regulation of private behavior via judicial and administrative process. The paper presents a model in which the law makes the agent's fine depend on the presentation of evidence whose production cost, in turn, depends on how the agent has behaved in the regulated activity. The targeted behavior becomes more privately beneficial to the agent to the extent that it reduces the agent's evidence costs and so improves its highest obtainable payoffs (net of costs) at the subsequent hearing. This view of evidence production has several notable implications, including that truth-finding has no direct role in deterrence, that non-falsifiable evidence, even when available, is unlikely to be the best choice for the system, and that "overdeterrence" may well be cost effective.