I agree with Bose's assumptions I'm afraid. There may have been an additional factor such as reduction in power which contributed, and as a result of the reduced safety margins sealed their fate.
It also shows that no matter what happens you should *never* try to "stretch the glide" - or in other words yank it over something, for this will have a certain outcome. It is better to fly into tree tops, but still fly, than stall and nose it in out of control. Nose first from 50' will kill you just as easily as nose first from 5,000'.
If you really have no options left, a better option would be to put in all flap, balloon over whatever it is and accept the consequences later - just don't stall. Ernest K Gann managed to avoid taking out the Taj Mahal this way when he took off in a (unknown to him) massively overloaded aeroplane.