This article explores the tension in modern criminal procedure between the goal of ascertaining the material truth of the criminal charge and the respect for important human rights of criminal suspects during the investigation of the alleged criminal responsibility. It examines two major areas where police run the risk of violating and often do violate the constitutional rights of criminal suspects during interrogations and during invasions of privacy in the form of dwelling searches and interception of confidential communications. The approaches of modern democracies to this dilemma run from the strict exclusion of all direct and indirect evidence (fruits of the poisonous tree), whenever a substantial constitution right is violated, to a discretionary approach, which balances various factors, including the need to ascertain the truth before deciding whether to use the evidence. The ambition of the article is to draw clear lines between when courts should exclude evidence and when discretion can reign.
Thaman, Stephen C., Constitutional Rights in the Balance: Modern Exclusionary Rules and the Toleration of Police Lawlessness in the Search for Truth (2011). University of Toronto Law Journal, (2011), v. 61, 691-735.