This article explores the use of covert online investigative methods by state agencies, and by individuals and institutions in civil society. Our focus is primarily on active investigations of online child exploitation. In particular, we are concerned with two types of investigative activity-- a) an investigator’s active deceptive impersonation of a child or of a facilitator of child exploitation, online; and b) techniques of accessing and compromising information systems used for the purpose of child exploitation. While these investigative methods may have a legitimate place in contemporary crime control, they do pose problems. We look first at their potential for abuse by state agencies, and the remedies available to the targets of illegal or otherwise questionable state practices. We then turn to non-state investigators, and note that the targets of private investigation have even less protection. We conclude by articulating some standards by which the propriety of state and non-state covert online investigative activity may be evaluated.