"The National Transportation Safety Board determines that the probable cause of this accident was the captain's inappropriate response to the activation of the stick shaker, which led to an aerodynamic stall from which the airplane did not recover." - From the Colgan Air crash Flight 3407
The NTSB findings suggest that inappropriate response to stick shaker was the cause for the crash which could have been avoided if the pilot reduced the AoA, a Deep stall would be impossible (or almost impossible) for the pilot to recover from, so its reasonable to believe that the DASH8 suffered a normal stall and not a deep stall.