Globalisation of crime poses a serious threat to the international community and is a matter of growing concern to law enforcement agencies all over the world. In the combat against international and organized crime, the European Union (EU) has supported a number of research and development projects within the domain of law enforcement focusing on cross-border communication, information extraction and data analysis in a multilingual context as well as terminology and knowledge management. LinguaNet is a case in point and the only project involving a multilingual messaging system. A high level of user involvement was a prominent feature of the project and the resulting software – the LinguaNet system – has gained widespread recognition and usage. The paper gives an overview of the LinguaNet approach as a whole emphasising the temporary experimental embedding of fully automatic MT in a multilingual messaging system. The system is intended for use by professionals with no background in linguistics but in great need of fast and robust communication. One of the conclusions drawn from this experiment is that authoring errors proved to be much more counter-productive than insufficiencies of MT. Another conclusion is that it is preferable to leave it to the recipient of a message to request a machine translation rather than providing it automatically up front. In more general terms, the police liked the approach and reported the need for more message type templates and MT facilities. Finally, the project led to the formation of a European LinguaNet user group network.