I’m afraid this kind of thing happens all the time which is why it is so important to copyright your images. We work in an industry where we are continually trying to understand the humanity we live in. It hurts so much more when we are burned by one of our own (or someone who we think is one of our own).
Photographer Kevin German was born in the Pacific Northwest of Washington and now is living in Ho Chi Minh City, Vietnam. (see his Web site here) Read his first-hand account of getting ripped off by someone he thought he could trust on his blog Wandering Light (here).
Not only was his content stolen, but a cutline (caption) for an image was fabricated. Germain said he has uploaded all his RAW images to http://www.copyright.gov and will soon be adding water marks to all his blog images. Unfortunately, these are both pretty good ideas.
Also – The guy’s pictures are worth a look (here).