In Germany, as in Spain and Poland, data collection primarily has to rely on media reports stored in the digital archives of news agencies and newspapers. The main source of information it the digital archive of the Deutsche Presseagentur (dpa) which contains a vast number of crime reports, supplemented by reports from ca. 25 regional newspapers. The full-text search in the dpa archive using a complex search string produced around 130.000 hits, most of which were of course false-positives. With the help of Prof. Ulrich Heid and Julia Weidenkaff, Institute for Natural Language Processing at the University of Stuttgart, we identified 920 cases of HS with 1100 victims, plus additional cases of attempted homicides followed by suicide making it by far the biggest national sample.
For a random sub-sample of ca. 350 cases, we collect additional in-depth information from prosecution files. Also, semi-structured interviews with surviving perpetrators in a still smaller sub-sample of HS cases is planned.