Criminal practitioners must develop a working knowledge of the state's investigative tools in order to provide emergency legal advice to a detainee. Such knowledge is also critical for providing an opinion of the legality of a state official's conduct after an investigation is complete.
As a starting point, counsel must become familiar with the specific legal authority for each investigative technique, including knowledge of the necessary preconditions for use and the terms of execution.
Counsel’s advice must also be informed by day-to-day police practice, including the study of tactical strategies that have evolved within the limits of the law.
Counsel should also appreciate the interaction between different methods of investigation. For example, the information obtained from one method may provide the foundation needed for the use of another technique, such as a successful interrogation leading to a warrant to search. In addition, there may be more than one viable pathway for a state official seeking to obtain evidence, such as a search based upon an informed consent in lieu of a search pursuant to a warrant.