2018 Volume 28 Issue 3 Pages 253-258
This study examined the effectiveness of author verification in the “PC remote control virus” case. We compared nine anonymous texts, written in the series of the “PC remote control virus” case, with five control texts and several irrelevant texts. The control texts were the series written in the “nomaneko” case, the criminal, Mr. K, had been arrested and confessed before committing the “PC remote control virus” case. The irrelevant texts were written by ten bloggers of the same gender and age as Mr. K, and several letters claiming responsibility or threats in the past cases. We conducted hierarchical cluster analysis on the following aspects of writing style: (1) rate of usage of non-independent words, (2) trigram of parts-of-speech, (3) bigram of postpositional particles, and (4) bigram of characters. The results indicated that the anonymous nine texts were arranged identically or similarly to the clusters of the control texts, whereas they were arranged differently from each authorship cluster in the irrelevant texts. These results suggest that the texts written in both the “PC remote control virus” case and “nomaneko” case were written by same author.
