So-called fact-finding or truth-seeking procedures are widely deployed, often, in the form of mechanisms that function either before (in preparation of), in addition to, or else, as an alternative to criminal justice – when the latter is inaccessible. Indeed, reality often requires to fill the blind spots of the so-called "fight against impunity" for the most serious crimes, and to act through non-prosecutorial and extrajudicial means where retributive justice is insufficient, excluded, uncontemplated or unthinkable. These situations lead to the development of other justice mechanisms, such as truth and/or reconciliation commissions. Like the work of judicial authorities, the endeavour of these commissions involves uncovering the traces / remains of crimes and responsibilities, which allows the realization and effective implementation of the right to the truth or the right to know. Nevertheless, these extrajudicial practices are plural and polymorphous, and they use disparate procedures for the establishment of facts. This testifies to a need for new theoretical approaches. This article addresses the importance of a critical perspective when analysing such extrajudicial mechanisms, as well as a series of key questions, in light of the complex plurality that needs to be apprehended.