They're accused of opening short positions, then pumping and dumping to trigger the shorts. That's not arbitrage.
By "pumping and dumping" do you mean "buying and selling" to outsmart other people trying to outsmart them?
Did they lie about the financial health of the securities they traded?
What? “Opening short positions then pumping and dumping to trigger the shorts” doesn’t make any sense at all. You’re saying they opened a position that profited if the price went down then they bought to raise the price