Good article on forensic linguistics in the Washington Times, with input from well-known forensic linguists (via Forensic Linguistics list).
Inter alia, Ted Kaczynski, the Unabomber, was pinned down because he wrote, ‘You can’t eat your cake and have it too’, a less common form than ‘You can’t have your cake and eat it too’, but more correct and used in middle English.
bq. Matters can be as simple as knowing that a fourth-grade dropout is unlikely to write a purported written confession to police containing the words “this perpetrator then approached my vehicle,” and as complicated as recognizing the existence of individual dialects and geographical disparities in certain words or phrases that aren’t always in the dictionary. Thus, a strip of land beside a street curb may be known variously as a “tree box,” a “county strip” or a “devil strip.”