Open-source technologies (OSINT) are becoming increasingly popular with investigative and government agencies, intelligence services, media companies, and corporations. These OSINT technologies use sophisticated techniques and special tools to analyze the continually growing sources of information efficiently. There is a great need for professional training and further education in this field worldwide. After having already presented the overall structure of a professional training concept in this field in a previous paper [25], this series of articles offers individual further training modules for the worldwide standard state-of-the-art OSINT tools. The modules presented here are suitable for a professional training program and an OSINT course in a bachelor’s or master’s computer science or cybersecurity study at a university. In this part 1 of a series of 4 articles, the OSINT tool RiskIQ PassivTotal [26] is introduced, and its application possibilities are explained using concrete examples. In part 2 the OSINT tool Censys is explained [27]. Part 3 deals with Maltego [28] and Part 4 compares the 3 different tools of Part 1-3 [29].