The next chart includes after hours trade, which shows that the market made a brief foray above the resistance zone which I have been illustrating for weeks now, but is now trading back within that zone. False signals can often be more powerful than signals that follow through. In this case, pending the confirmation of a move below today's low, the false upside break could lead to a sharp decline.
To further illustrate the false upside break followed by the all day sell off, I have included an hourly candlestick chart showing the action since the end of March. It shows frenzied traders bidding up the market to over 4400 in pre-market trade just before 10am, then selling off all day. Could the pre-market action have been a blow-off?