This stuff is hardly surprising.
"The letter then goes on to say that while some negative reports on Chinese companies listed in the US have “helped cleanse the environment”, the likes of Citron have “started targeting legitimate companies with either no problems or minimal problems”, and done nothing but tell bold-faced lies."
The technique of short selling, most particularly so-called "naked shorting" (where you simply borrow shares you are fucking with investing in rather than having to pony up anything yourself), has a thoroughly pernicious effect given that it positively begs market manipulators/sharks to get involved. When in engaging in this type of "investment" the opportunities/temptations for fraudulent behaviour are so obvious that it is inexcusable that the exchanges have not yet banned at least the "naked" version of the practice.