It is not unusual for a corporation or individual to be angry that their property has been defaced. Sometimes the content of the graffiti is damaging to the morale of the office. Graffiti is a crime that should be taken seriously.
Often the writer of graffiti thinks his or her handwriting is drastically different from his or her regular writing. More often than not, the graffiti is a thinly disguised version of a person's writing and can be easily identified.
On the flip side, perhaps you have been accused of writing some graffiti and are about to lose your job over it. Maybe the neighbors silently scorn you, and you want to prove your innocence.
Most cases of this type are handled by photograph, although I have had a portion of a wall shipped to me before! Please call before the graffiti is destroyed if possible, so I may best advise you of how to handle it.