The article is short on details, but it sounds to me as if it was (most likely) MS Word Document metadata, rather than the floppy itself, which provided vital clues, though file deletion was another culprit:

http://www.abajournal.com/magazine/article/how_the_cops_caug... (relevant details near end of article).

That's what Wikipedia has, and the implication from this Times story http://www.nytimes.com/2006/04/05/technology/techspecial4/05... that it draws from.

Thanks, good info.

This case is really interesting.

Here's a guy who had committed numerous murders, and gotten away with it to boot. But he had to have the recognition. Criminal psychology is fascinating stuff.