Dataharvest 2026 - the European Investigative Journalism Conference

Police work is notoriously difficult to investigate. While police actions directly affect fundamental rights and guide politics and law-making, official data on their influence is scarce.

In this session, we will share some tools and methodologies on how to investigate the police sources. We will draw on more than ten years of investigations into different aspects of police violence and state abuse of power in Germany. We will also show how the data-driven journalism tools can help to make the underlying structures more visible, and present our recent investigation into police unions in Germany: who they are, want they stand for and how they influence the public debate and politics. We pieced together data from different sources and combined it with investigative journalism to draw the full picture.

We want to show how it is possible to do a data-driven investigative story despite missing data. We will focus on the following questions:

- How to build your own datasets when no official statistics exist? Which public data sources about the police are available? Which data can we get from ministry inquiries? What about social media?
- How to clean up, classify and analyze the data? Which tools are helpful in combining manual and automated workflows?
- How to tell a complex data-driven story without this one headline? What are judicial and editorial hurdles when publishing a sensitive topic?
- What can investigative and data journalists gain from close collaboration? What worked well? What would we do differently?