This almost sounds like it was taken from a movie plot. According to an article on buddhism.kalachakranet.org, Beijing Police disguised as Monks are orchestrating the Tibet riots. The photo below was allegedly taken by a satellite in 2003, where you can clearly see Beijing Officers holding what appears to be Monk garments.

I wouldn't say it's conclusive proof but I would say this sort of action is in line with something you would expect from the propaganda communist capital of the world.