The aim of the considerations undertaken in the article is to characterize the grounds for applying a preventive measure in the form of pre-trial detention based on operational information. A comparative analysis of the reasons for applying this measure on general terms and in cases of terrorist offenses was carried out. On the basis of archival files, the circumstances of Tadeusz Bejt’s abduction from Berlin were discussed. His post-war fate was presented, when, on the orders of the intelligence service, he was unjustifiably deprived of his liberty and, consequently, sentenced to death. Bearing in mind the need to effectively prosecute the perpetrators of terrorism, the article contains proposals for changes in the law in the field of unifying the conditions for the use of an isolating preventive measure.