The issues addressed are whether intelligence services have a discretionary power to determine which intelligence will be provided to criminal justice professionals involved in the processing of terrorist suspects' cases; the relationship between such discretion and the corresponding legal duty of secrecy and the rights of the defense and the judicial review of the lawfulness of that information; and whether prosecutors should trust the discretionary judgment of the intelligence services and the lawfulness of the means by which the intelligence information was obtained. Further, the author addresses whether it is up to the prosecutor to decide whether such intelligence is used as secret evidence. This paper examines the historical background for the sharing of information between the intelligence community (IC) and the law enforcement community (LEC) in Europe and the United States. This is followed by an analysis of information sharing between the IC and the LEC up to the terrorist attacks in the United States on September 11th. This includes discussions of the development toward security-oriented criminal law, information sharing between the IC and LEC prior to September 11th, and the balance between national security and the right of due process in criminal proceedings. This is followed by sections on information sharing between the IC and LEC under the post-September 11th U.S. Patriot Act, the analysis of the sharing of intelligence and investigation information in the Netherlands, and the status of the European Convention on Human Rights with respect to the use of intelligence in criminal proceedings. The thread running through this analysis is that counterterrorism measures should not undermine the traditional foundation of the rule of law and the public administration of criminal justice.