I don't know how accurate the flight tracking records on FlightAware.com are, but it seems that the aircraft made a sudden 90deg turn to starboard at 12:33 and dropped below its stall speed at 12:35, but maintained FL260:
FlightAware > Flight Track Log > N950KA > 07-Jun-2012 > KFPR-3JC
It then returned to 255kts for three minutes before starting a descent.