They probably got their hands on a block of stock (either open market or from company), and are just selling it into the market at certain times to make those low stock trade data points used to calculate conversion prices ... would be pretty easy ... not sure of the legality but it would be very hard to prove manipulation probably...
The note holder shorts the stock ahead of his option to convert his loan into stock so getting more stock at a lower price. Once these shorts are out of the way the stock should rise.
News 
Market Data 
Discover 
