Русско-англо-русский юридический словарь

Direct evidence supports the truth of an assertion (in criminal law, an assertion of guilt or of innocence) directly, i.e., without an intervening inference. (Wikipedia)

Primary sources are documents, images or artifacts that provide firsthand testimony or direct evidence concerning an historical topic under research investigation. Primary sources are original documents created or experienced contemporaneously with the event being researched. (UC Irvine Libraries)