A Language Modelling Approach to Linking Criminal Styles with Offender Characteristics

Abstract

The ability to infer the characteristics of offenders from their criminal behaviour ('offender profiling') has only been partially successful since it has relied on subjective judgments based on limited data. Words and structured data used in crime descriptions recorded by the police relate to behavioural features. Thus Language Modelling was applied to an existing police archive to link behavioural features with significant characteristics of offenders. Both multinomial and multiple Bernoulli models were used. Although categories selected are gender, age group, ethnic appearance and broad occupation (employed or not), in principle this can be applied to any characteristic recorded. Results indicate that statistically significant relationships exist between all characteristics for many types of crime. Bernoulli models tend to perform better than multinomial ones. It is also possible to identify automatically specific terms which when taken together give insight into the style of offending related to a particular group.

Conversational content in the context of safety of social networks

“…Style-based approach is used for examination of chat messages according to changes in writing style of the author. According to F. Crestani [18], neither of these two approaches tries to solve content identification and authorship of the conversational content at the same time. Despite the fact that these two challenges are considered as different ones, there is a strong relation and dependency between the conversation theme and conversation author.…”

Estimating real-valued characteristics of criminals from their recorded crimes

“…Language Modelling techniques have also been used for the profiling problem where characteristics of the offender were categorical e.g. gender or ethnic group [1,2] where the description of the crime was reduced to a bag of words. However such an approach is problematic for charcteristics defined on a numerical scale such as age or distance travelled.…”