Internal investigations play an important role in criminal proceedings in the United States, especially
since the publication of the Yates Memorandum: it reminds the prosecutors of article 9-28.210 U.S
Attorneys Manual, an article that establishes the importance of determining individual responsibility
for criminal acts within a corporation. The cooperation of the corporation in establishing individual
responsibility should be an important part in the analysis whether the corporation has sufficiently
assisted the authorities. The most important way of collaboration and tool to determine individual
responsibility is through adequate internal investigations, which corporations conduct following the
indications that the government have set. This scenario has generated an important specialization in
the world of internal investigations which has to be known not only by American lawyers, but also by
lawyers in other countries, due to international internal investigations which have become very
common in practice. Therefore, this article will focus, from a practical point of view, on the steps to
be taken to conduct an adequate internal investigation according to the ‘American way’. In particular,
this article will analyze aspects such as why the internal investigations should be conducted by
external lawyers, which alerts should lead to start an internal investigation, the planning of an
investigation, how to react to the crisis moment, how to secure the information and how to conduct
employee interviews. It will also discuss the client-attorney privilege in internal investigations
(Upjohn v United States) and how to present the investigation conclusions to the corporation.