Meditating dead monks
I tired to answer that question on another site: see this answer.

In summary I think (based on my reading, not being an expert) that "tukdam" means 'dead and meditating' or 'meditating after death' (so, it doesn't mean, 'not dead' or 'body not dead').

The news article hyperlinked in that question includes a picture of the monk's mummified (dead) body.