The following paper deals with the issue of disguise in incriminated writings within the framework of forensic authorship assessment. Although it does not seem to be widely known among linguistically untrained speakers that written language can indeed contain traces of the individual author and that these traces may be detected by a linguist, authors of incriminated writings such as extortion letters or threatening letters frequently attempt to disguise not only their handwriting, but also their language. Everyday practice points to a number of possible strategies of disguise which, however, have not as yet been empirically investigated. In order to acquire some empirical data a study was carried out with 52 students of German Studies, the results of which are presented and discussed. Although the results remain to be tested against data acquired under more representative conditions, different strategies of disguise can indeed be distinguished which may facilitate the forensic linguist's task of identifying disguised as opposed to authentic language in written texts. Also, it is suggested that the results of an experiment such as the one outlined here may contribute to research into issues concerning the general metalinguistic knowledge of native speakers in general.