Txt Crimes, Sex Crimes And Murder: The Science Of Forensic Linguistics

At the BA Festival of Science in Liverpool on September 8, Dr Tim Grant, the Deputy Director of the Centre for Forensic Linguistics at Aston University, will describe how language analysis is increasingly playing a key part during police investigations and court cases to help identify the author of incriminating material, whether it be a threatening note, documents planning a terrorist attack or a sexually explicit chat room conversation involving an adult and a child.

He believes that, despite public concerns about the growth of a surveillance society, the ability to identify authorship of electronic communications is beneficial.

Linguistic evidence demonstrating who sent a particular text message has been significant in a growing number of cases where criminals have attempted to use them as alibis. These include difficult murder cases where victims’ bodies were never found, such as the recent prosecution of David Hodgson, who was convicted in February of the murder of his ex-lover Jenny Nicholl. Her body has never been found.

Dr Grant explains: ‘Jenny Nicholl disappeared on 30th June 2005. A linguistic analysis showed that text messages sent from her phone were unlikely to have been written by her but, rather, were more likely to have been written by her ex-lover, David Hodgson. A number of stylistic points identified within texts known to have been written by Jenny Nicholl were not present in the suspect messages. Instead, these were stylistically close to the undisputed messages of David Hodgson.

Hodgson was convicted partly because, in text messages he sent on her phone after she disappeared, he spelled "myself" as "meself".  In her own text messages, Nicholl had spelled the word "myself".

‘The kind of features we were interested in were the shortening of “im” in the texts from Nicholl contrasting with “I am” in the suspect messages and the lack of space after the digit substitution in items such as “go2shop” contrasting with “ave 2 go”’.

Dr Grant has put together a database of more than 7000 texts as part of his research into text messaging style and variation between individuals and groups of individuals. The public can contribute to his ongoing research by submitting text samples to http://www.forensiclinguistics.net/texting. His study seeks to establish base rate information for certain features in texting language, and will also highlight how groups of people who text one another frequently grow more similar in their texting style.

Based on techniques that were first used to measure similarity between marine ecosystems, and then applied to the analysis of sexual crime, Dr Grant has now developed a method to quantify people’s style of text writing. His technique, which assigns a numeric measure of stylistic difference between any two texts, encourages the move from expert opinion based evidence to more methodologically rigorous and empirically tested techniques.

‘Forensic linguistics is a relatively new forensic science but the Council for the Registration of Forensic Practitioners opens a linguistic subregister this month and this will give easy access to reputable practitioners and help cement its position as a key forensic science,’ said Dr Grant.

‘In addition to this formal recognition we are seeing an expansion in casework, particularly in the area of electronic communication – SMS, IRC (internet relay chat) and email. In these kinds of communication it is relatively easy to be, or at least feel, anonymous – new technologies have created an anti-social phenomenon of mass anonymity, and the ability to identify the writer can only be beneficial for society.’

Dr Grant will be presenting this material in his talk at the BA Festival of Science, ‘The BA Joseph Lister Award Lecture – Txt crimes, sex crimes and murder: the science of forensic linguistics’.