This article analyses how judicial activity in domestic prosecution of dictatorship-era human rights violations shapes and contributes to the accumulation and verification of archival evidence. In particular, it discusses the ways in which trials challenge the status of existing sources of truth, such as truth commission findings, as well as producing new kinds of information and new sources of doubt about crimes of the recent past. The paper argues that novel 'truth orders' are produced by transitional artifices such as the truth commission and other administrative instances. Trials constitute another such order, with a separate and in some senses more socially established claim to legitimacy. It is in some senses inevitable, therefore, that competing truth claims arise when prosecutions are added to the post-transitional mix. Particular aspects of the technically challenging process of investigating long-ago crimes introduce additional professional considerations. The procedures and protocols applicable to forensic science and police work must be assimilated and evaluated by judges charged with turning old and new data into usable evidence. The particular rules of evidence, probatory value, and standards of proof that judges are mandated by law to apply challenges and transforms, in sometimes unpredictable ways, the social legitimacy or veracity previously attributed to such data.