Frequently, in cases where the extortionists establish contact by means of text, the authorship identification experts are in great demand, as this specialization is offered solely by the BKA. The writings which are examined are either incriminating manuscripts which play a role in connection with criminal offences, as are texts from the right or left wing extremist terrorist spectrum, claiming responsibility for attacks for example, or texts which constitute a criminal offence per se, for instance threats; but in the main, however, extortion letters.
Depending on the question, anonymous texts undergo text analysis or text comparison, and a corpus search. When playing a role in ongoing investigations, the aim of text analysis is to get biographic statements about the place of origin, age and activity of the author, among other things. No psychological profile is prepared. The text comparison, usually requested by the courts or the prosecutor’s office, comprises a comparison of several anonymous texts or those of known origin, e.g. from suspects, with one another, in order to derive links or excluding factors. During the corpus search, a comparison with incriminating letters from other criminal proceedings takes place, which, based on a legal mandate, are kept at the BKA.
Linguistic analysis in KISTE
The text examinations are methodologically based on a style and error analysis, which categorizes language characteristics, thus making them interpretable. This analysis and the management of the text corpus take place in KISTE, (Forensic Information System: Texts), a unique expert system, which offers experts support during the stages of linguistic processing, systematisation, and archiving. This information system is a crucial tool for the rendering of an expert opinion since it offers a variety of analysis instruments, such as searches, background statistics, and analyses of similarities.
The authorship identification complies with the demands of the BKA’s quality management systems by utilizing methods which are certified by DIN EN ISO/IEC 17020 standards.