In this experiment, we find that features which model interaction andconversational behaviour contribute well to identifying sexual grooming behaviourin chat and forum text. Together with the obviously useful lexical features —which we find are more valuable if separated by who generates them — weachieve very successful results in identifying behavioural patterns which maycharacterise sexual grooming. We conjecture that the general framework can beused for other purposes than this specific case if the lexical features are exchangedfor other topical models, the conversational features characterise interaction andbehaviour rather than topical choice.