The work focuses on data collection and data processing prior to the initial suspicion in criminal proceedings, which has gained relevance particularly due to the case law of the Federal Constitutional Court regarding data retention. Preliminary investigations conducted with the aim of examining a situation for sufficient factual indications can be incorporated into the Code of Criminal Procedure, provided that the principle of proportionality is strictly observed. Against this background, the study explores the limits and possible design of a preliminary investigation procedure, the legal status of those affected by preliminary investigations, the issue of legal protection against preliminary investigation measures, as well as the problems arising from the transmission of data from a preliminary investigation to another criminal proceeding or for preventive police purposes. The findings are reflected in a draft regulation, with the author advocating for a conscious abstention from data collection prior to the initial suspicion in criminal proceedings for liberal rule-of-law reasons.