September 18, 2015
It is nowadays a common phenomenon in movies to analyse the personality of a criminal by scrutinising his mobile and online messages, and finding a pattern for identifying him. Cyber crime investigation experts say that this technique is gaining speed and favour in real cyber crime investigation too.
Termed ‘stylometry’, this is considered an effective investigation tool to determine the character of a criminal. Through this technique, the analysis of a suspect is made using his pattern of writing, choice of words, syntax usage, use of punctuations or lack of it, spelling mistakes, which are unique to each individual, etc.
Yet, stylometric evidence is not allowed to be produced in the Indian courts, though they are permissible as evidence in courts in the West.
A cyber expert who has been helping the city police in cracking cyber crime cases says that he recently used stylometry in a case where they zeroed in on an MBA graduate who had been harassing a woman with lewd and threatening emails.
“The content could be typed out or handwritten. Information about the person can be deciphered from that. The strokes, the choice of fonts, the colours used could also mean a lot. Usage of different colours on the same word could mean anger, passion and confusion”, he says.
This technique was earlier used to identify authors of plays, novels and articles. Stylometry has also helped pin down plagiarists. Now this has been widely used in cracking Nigerian scams where the mails use flamboyant language, long and complex sentences and content that could be factually incorrect, the expert adds.
A trainer who has been training people on forensics and cyber crime investigation says that the mindset of the criminal can be deciphered from the tone of the message. This is easily identifiable in cases where disgruntled employees send threatening e-mails to their bosses.
“When there is absolutely no lead, stylometry comes as the first choice. Age of the suspect and the background from which he comes from can be determined. While there are organisations in the US working on stylometry, there are no studies on Indian rating. This is still an emerging technique in India,” he adds.
A team of students did a research on the technique using a data base of 20 GB emails. One among them says that they were able to distinguish the gender, their educational discipline and the kind of schooling the criminals had. The place from which they hailed from could also be determined, somewhat broadly.