There are many cases of pump n       dump manipulations.

Recently a Hong Konger has  been    arrested for stock manipulation. It is like fishing tactic, as u pull the fishing line up quickly, the fish may              rush  forward to eat n get caught.

As in stock pump n dump cases, the manipulators push up the prices by purchasing at market prices big quantities of shares. As the price rises, it attract small speculators thinking  that good news is coming. The next 

day or a few days later, the volume     has disappeared, the manipulator has made enough profit n leave the counter.   Traders beware!