Learn the identity of a graffiti tagger

This case involved a case where someone wrote graffiti on a bathroom wall at a construction site. The foreman of the construction site suspected one of his employees as having performed the writing. Since the writing was on a wall a digital photograph was taken to capture the image of the graffiti writing. The attorney sent the image and examples of the suspect’s regular course of business writing to me.

The client wanted to know whether the suspect was the author of the graffiti.

Using Photoshop I extracted portions of the unique character formations from the suspect’s known writing. These unique formations are known as individualizing characteristics of the writing. These are the characteristics that identify he writing as belonging to a specific writer. The graffiti was examined to learn whether it contained th individualizing characteristics in the suspect’s writing.

The image shows how the individualizing characteristics in the known writing were overlayed onto the same letters in the graffiti. The purpose is to learn whether they match.

An Unsolved Graffiti Case

Finding one or two matches of the individualizing characteristics in the graffiti does not make a match between the suspect and the questioned writing. In this case there were many consistent matches with the graffiti. These many consistent matches and no significant differences lead to an opinion identifying the suspect as the writer of the graffiti.

In another graffiti case the client was a local business. Someone wrote a nasty note on toilet paper about a manager. The company showed me employment records of five people they suspected as being the potential graffiti writer. In this case I narrowed the list of suspects to two or three. There was an insufficient amount of handwriting to reach a determination one suspect was more likely than others. The company decided not to pursue the matter.